Functional Groups Dominate Aboveground Net Primary Production under Long-Term Nutrient Additions in a Tibetan Alpine Meadow.

Anthropogenic nutrient additions are influencing the structure and function of alpine grassland ecosystems. However, the underlying mechanisms of the direct and indirect effects of nutrient additions on aboveground net primary productivity (ANPP) are not well understood. In this study, we conducted an eight-year field experiment to explore the ecological consequences of nitrogen (N) and/or phosphorous (P) additions on the northern Tibetan Plateau. ANPP, species diversity, functional diversity, and functional groups were used to assess species' responses to increasing nutrients. Our results showed that nutrient additions significantly increased ANPP due to the release in nutrient limitations. Although N addition had a significant effect on species richness and functional richness, and P and N + P additions altered functional diversity, it was functional groups rather than biodiversity that drove changes in ANPP in the indirect pathways. We identified the important roles of N and P additions in begetting the dominance of grasses and forbs, respectively. The study highlights that the shift of functional groups should be taken into consideration to better predict the structure, function, and biodiversity-ANPP relationship in grasslands, particularly under future multifaceted global change.

Resource co-limitation of community biomass but not structure of an alpine grassland.

Anthropogenic environmental changes are influencing the structure and function of many ecological communities, but their underlying mechanisms are often poorly understood. We conducted a 7-year field experiment to explore the ecological consequences of nitrogen (N) and phosphorous (P) enrichment in a high-altitude Tibetan alpine grassland. We found that the enrichment of both N and P, but not either alone, increased plant above- and belowground biomass. In contrast, N, but not P, enrichment reduced species richness and altered plant phylogenetic diversity and structure. Whereas plant species loss and changes in phylogenetic structure were mainly driven by higher soil manganese levels under N addition, they were mainly driven by increased plant belowground biomass under the addition of both N and P. Our study highlights the resource co-limitation of community biomass but not the structure of the study grassland, while also identifying soil metal toxicity and belowground competition as important mechanisms driving community changes following nutrient amendment.

Winter warming alleviates the severely negative effects of nitrogen addition on ecosystem stability in a Tibetan alpine grassland.

Many recent studies have explored how global warming and increased nitrogen (N) deposition affect the structure and function of natural ecosystems. However, how ecosystems respond to the combination of warming and N enrichment remains unexplored, especially under asymmetric seasonal warming scenarios. We conducted a decade-long field experiment in an alpine grassland to investigate the effects of warming (ambient condition (NW), winter-only (WW), and year-round (YW) warming) and N addition on the temporal stability of communities. Although N addition significantly reduced community temporal stability in NW, WW, and YW, WW relieved the severely negative effects of N addition compared to NW and YW (from 47.7 % in NW and 76.1 % in YW to 18.6 % in WW under 80 kg N hm-2 year-1). The most remarkable finding is that the main factors driving community stability shifted with warming patterns. The increase in community dominance under NW was a significant driver of the decreased temporal stability in the community. However, the decrease in community stability caused by N addition was ascribed to the decreased stability of both dominant and common species under WW. In contrast, N addition decreased community temporal stability mainly via a decrease in species asynchrony under YW. Our results suggested that warming patterns can modulate the effects of N enhancement on community stability. To predict the effects of climate change on alpine grasslands accurately, the idiosyncratic effects of asymmetric seasonal warming under future climate change scenarios should be considered.

Variation of plant CSR strategies across a precipitation gradient in the alpine grasslands on the northern Tibet Plateau.

Identifying ecological strategies based on functional traits can help us better understand plants' adaptations and changes in ecological processes, and thus predict the impact of climate change on ecosystems, especially in the vulnerable alpine grasslands. Herein, we investigated the plant CSR strategies of four grassland types (alpine meadows, AM; alpine meadow steppes, AMS; alpine steppes, AS; and alpine desert steppes, ADS) and its functional groups (grasses, sedges, legumes, and forbs) along the east-to-west gradient of decreasing precipitation on the northern Tibetan grasslands by using Grime's CSR (C: competitor, S: stress tolerator, and R: ruderal) analysis. Although alpine grasslands were dominated by S-strategy, our results also indicated that AM with higher water, nitrogen (N) and phosphorus (P) availability had significantly lower S-strategy values and relatively higher C- and R-strategy values (C: S: R = 6: 63: 31 %) than those in AMS (C: S: R = 3: 94: 3 %,), AS (C: S: R = 3: 87: 10 %), and ADS (C: S: R = 1: 94: 5 %). The CSR strategy values of forbs and legumes showed greater variability compared with grasses and sedges in the environmental gradient. Furthermore, water variability on the precipitation gradient eventually affected plant traits and CSR strategies through soil N and P availability and pH. Our findings highlighted that plant CSR strategies were regulated by the availability of soil resources, and plants adopted more flexible adaptation strategies in relatively resource-rich environments. This study sheds light on the mechanisms of plant adaptation to the changing environment in the alpine grasslands.

Mitochondrial DNA haplogroup F confers genetic susceptibility to chronic HBV infection for the Yi nationality in Lijiang, China.

Mitochondria are essential for hepatitis B virus (HBV) infection. Moreover, the findings of our previous study indicate that host mitochondrial genetic factors are associated with chronic hepatitis B (CHB) for the Han Chinese. However, in terms of genetic heterogeneity, the impact of mitochondria on host susceptibility to HBV infection in ethnic minorities in China remains unclear. Here, a total of 7070 subjects who had visited the hospital between June 1, 2019, and April 31, 2020, were enrolled for seroprevalence of HBV infection investigation. A total of 220 individuals with CHB (CHBs) and 223 individuals with a trace of HBV infection (spontaneously recovered subjects, SRs) were analyzed for mitochondrial DNA (mtDNA) sequence variations and classified into respective haplogroups. Haplogroup frequencies were compared between CHBs and SRs. Among eight nationalities, Yi nationality patients had the highest HBsAg prevalence rate (27.9% [95% CI: 25.3%-30.5%]) and the lowest vaccination rate (4.9% [95% CI: 3.7%-6.2%]). After adjustment for age and gender, haplogroup F was a risk factor for CHB infection (P = 0.049, OR = 2.079, 95% CI = 1.002-4.31), while D4 had a significant negative correlation with the HBeAg-positive rate (P = 0.024, OR = 0.215, 95% CI = 0.057-0.816). Together with our previous study, the findings indicate that different nationalities have different genetic susceptibility to HBV infection.

Functional identity of leaf dry matter content regulates community stability in the northern Tibetan grasslands.

Biodiversity-stability mechanisms have been the focus of many long-term community stability studies. Community functional composition (i.e., functional diversity and functional identity of community plant functional traits) is critical for community stability; however, this topic has received less attention in large-scale studies. Here, we combined a field survey of biodiversity and plant functional traits in 22 alpine grassland sites throughout the northern Tibetan Plateau with 20 years of satellite-sensed proxy data (enhanced vegetation index) of community productivity to identify the factors influencing community stability. Our results showed that functional composition influenced community stability the most, explaining 61.71% of the variation in community stability (of which functional diversity explained 18.56% and functional identity explained 43.15%), which was a higher contribution than that of biodiversity (Berger-Parker index and species evenness; 35.04%). Structural equation modeling suggested that functional identity strongly affected community stability, whereas biodiversity had a minor impact. Furthermore, functional identity of leaf dry matter content regulated community stability by enhancing species dominance (Berger-Parker index). Our findings demonstrate that functional composition, specifically functional identity, plays a key role in community stability, highlighting the importance of functional identity in understanding and revealing the stabilizing mechanisms in these fragile alpine ecosystems which are subjected to increasing environmental fluctuations.

[Innovative design of global change network control experiment: A case design of water and heat factors of grassland ecosystem in China]. / å ¨çƒå˜åŒ–è”ç½‘æŽ§åˆ¶å®žéªŒçš„åˆ›æ–°æ€§è®¾è®¡:ä»¥æˆ‘å›½è‰åœ°ç”Ÿæ€ç³»ç»Ÿæ°´çƒ­è¦ç´ è”ç½‘æŽ§åˆ¶å®žéªŒä¸ºä¾‹.

Global changes have profound impacts on the structure and function of terrestrial ecosystems. It is a prerequisite to realize the sustainable use of ecosystem to clarify the response and adaptation mechanism of ecosystems to global changes. Network of control experiment is an important way to understand the response and adaptation of the structure and function of ecosystems to global change factors at regional and global scales. The scientific top-level design is conducive to the integration, comparison and analysis of integrative network-data, and then supports the development of universal ecological theory. We comprehensively expounded the theoretical basis, methodological principles and brand-new concepts of experimental network design for future global change control experiment networks design from several aspects, such as research progress, development needs, innovative design and research prospects. Taking Chinese grassland ecosystems as an example, based on the concept of space reference points (mean point of water and heat), the innovative design technology system of China's grassland ecosystem networking experiment was proposed, in order to promote the development of networking research of control experiments at both regional and global scales in the future.

Community species diversity mediates the trade-off between aboveground and belowground biomass for grasses and forbs in degraded alpine meadow, Tibetan Plateau.

Although many empirical experiments have shown that increasing degradation results in lower aboveground biomass (AGB), our knowledge of the magnitude of belowground biomass (BGB) for individual plants is a prerequisite for accurately revealing the biomass trade-off in degraded grasslands. Here, by linking the AGB and BGB of individual plants, species in the community, and soil properties, we explored the biomass partitioning patterns in different plant functional groups (grasses of Stipa capillacea and forbs of Anaphalis xylorhiza). Our results indicated that 81% and 60% of the biomass trade-off variations could be explained by environmental factors affecting grasses and forbs, respectively. The change in community species diversity dominated the biomass trade-off via either direct or indirect effects on soil properties and biomass. However, the community species diversity imparted divergent effects on the biomass trade-off for grasses (scored at -0.72) and forbs (scored at 0.59). Our findings suggest that plant communities have evolved two contrasting strategies of biomass allocation patterns in degraded grasslands. These are the "conservative" strategy in grasses, in which plants with larger BGB trade-off depends on gigantic roots for soil resources, and the "opportunistic" strategy in forbs, in which plants can adapt to degraded lands using high variation and optimal biomass allocation.

Degradation shifts plant communities from S- to R-strategy in an alpine meadow, Tibetan Plateau.

The replacement of dominant sedges/grasses with secondary forbs is common in alpine rangelands, but the underlying plant ecological strategies and their relevance to leaf traits and their variabilities of different plant functional groups remain largely unknown. Here, we measured key leaf traits and analyzed the competitor, stress-tolerator and ruderal (CSR) strategies of major species with different functional groups (sedges, grasses and forbs) in an alpine meadow along a degradation gradient on the Tibetan Plateau. Our results indicated that S-selected species were dominant in both non-degraded (C:S:R = 1:95:4%) and severely degraded (C:S:R = 2:87:11%) meadows. However, there was a shift from S- to R-strategy in the communities after rangeland degradation. More specifically, sedges and grasses with a "conservative" strategy maintained stronger S-strategy to tolerate degraded and stressful conditions. In contrast, forbs with an "opportunistic" strategy (increase 9.5% in R-score) tended to adapt to degraded stages. Moreover, 51.1% and 23.9% of the increased R-scores in forbs were accounted by leaf mass per area and specific leaf area, respectively. Generally, higher leaf water and nitrogen contents coupled with larger variations in leaf traits and flexible SR strategies in forbs enabled them to capitalize on lower soil water and nutrient availability. Our findings highlighted that the contrasting strategies of plant species in response to the decrease in available resources might lead to niche expansion of secondary forbs and loss of diversity in the degraded alpine meadow. The emerging alternative stable states in the degraded rangelands might bring about a predicament for rangeland restoration.

[Preparation and Characterization of Clopidogrel Bisulfate Liposomes].

OBJECTIVE: To prepare encapsulated clopidogrel bisulfate (CLP) liposomes so as to deal with the poor water solubility of CLP, and to provide the experimental basis for the development of CLP formulations for intravascular injection. METHODS: CLP-loaded liposomes were prepared using thin film hydration/sonication method and pH gradient active drug loading technology. Then, the morphology, particle size, encapsulation efficiency, drug loading capacity, Zeta potentials and in vitro release behavior were characterized. Bilateral renal arteries of Sprague-Dawley (SD) rats were clamped with micro-artery clamps to establish the model of renal ischemia-reperfusion injury (IRI) in male SD rats. The study aimed to preliminarily investigate the therapeutic effect of CLP-loaded liposome pretreatment on renal IRI in rats. RESULTS: It was found that the optimal formulation and preparation technology of CLP liposomes were as follows: the CLP-to-phospholipid weight ratio of 1∶10, phospholipid-to-cholesterol ratio of 6∶1, octadecylamine-to-CLP ratio of 1.2∶1, PEG 400-to-CLP ratio of 1∶1, and incubation at 50 ℃ for 40 min. Then, following ultrasonication of 100 W efficiency at 5-second intervals for 20 times, CLP loading was conducted using 5 mL of 0.1 mol/L citric acid buffer at pH 3.0. Liposome samples were prepared with the film dispersion method, and the pH value was adjusted to 7.5 through pH gradient active drug loading technology. The CLP-loaded liposomes obtained in this way had a rounded shape, good dispersity, an average particle size of (134.13±2.60) nm, polydispersity index (PDI) of 0.25±0.02, and a Zeta potential of (2.12±0.23) mV. The encapsulation efficiency was found to be (98.66±0.14)%, and the drug loading capacity was (7.47±0.01)%. The in vitro release results showed that 66.24% of CLP was released cumulatively within 72 h. Preliminary efficacy experiments showed that animals pretreated with CLP-loaded liposomes had lower serum levels of blood urea nitrogen and creatinine compared to the levels of IRI model rats without any pretreatment. CONCLUSION: CLP-loaded liposomes were successfully prepared, which might provide the experimental foundation for the future development of CLP formulations for injection.

Microbial metabolic response to winter warming stabilizes soil carbon.

Current consensus on global climate change predicts warming trends with more pronounced temperature changes in winter than summer in the Northern Hemisphere at high latitudes. Moderate increases in soil temperature are generally related to faster rates of soil organic carbon (SOC) decomposition in Northern ecosystems, but there is evidence that SOC stocks have remained remarkably stable or even increased on the Tibetan Plateau under these conditions. This intriguing observation points to altered soil microbial mediation of carbon-cycling feedbacks in this region that might be related to seasonal warming. This study investigated the unexplained SOC stabilization observed on the Tibetan Plateau by quantifying microbial responses to experimental seasonal warming in a typical alpine meadow. Ecosystem respiration was reduced by 17%-38% under winter warming compared with year-round warming or no warming and coincided with decreased abundances of fungi and functional genes that control labile and stable organic carbon decomposition. Compared with year-round warming, winter warming slowed macroaggregate turnover rates by 1.6 times, increased fine intra-aggregate particulate organic matter content by 75%, and increased carbon stabilized in microaggregates within stable macroaggregates by 56%. Larger bacterial "necromass" (amino sugars) concentrations in soil under winter warming coincided with a 12% increase in carboxyl-C. These results indicate the enhanced physical preservation of SOC under winter warming and emphasize the role of soil microorganisms in aggregate life cycles. In summary, the divergent responses of SOC persistence in soils exposed to winter warming compared to year-round warming are explained by the slowing of microbial decomposition but increasing physical protection of microbially derived organic compounds. Consequently, the soil microbial response to winter warming on the Tibetan Plateau may cause negative feedbacks to global climate change and should be considered in Earth system models.

Nitrogen economy of alpine plants on the north Tibetan Plateau: Nitrogen conservation by resorption rather than open sources through biological symbiotic fixation.

Nitrogen (N) is one of the most important factors limiting plant productivity, and N fixation by legume species is an important source of N input into ecosystems. Meanwhile, N resorption from senescent plant tissues conserves nutrients taken up in the current season, which may alleviate ecosystem N limitation. N fixation was assessed by the 15N dilution technique in four types of alpine grasslands along the precipitation and soil nutrient gradients. The N resorption efficiency (NRE) was also measured in these alpine grasslands. The aboveground biomass in the alpine meadow was 4-6 times higher than in the alpine meadow steppe, alpine steppe, and alpine desert steppe. However, the proportion of legume species to community biomass in the alpine steppe and the alpine desert steppe was significantly higher than the proportion in the alpine meadow. N fixation by the legume plants in the alpine meadow was 0.236 g N/m2, which was significantly higher than N fixation in other alpine grasslands (0.041 to 0.089 g N/m2). The NRE in the alpine meadows was lower than in the other three alpine grasslands. Both the aboveground biomass and N fixation of the legume plants showed decreasing trends with the decline of precipitation and soil N gradients from east to west, while the NRE of alpine plants showed increasing trends along the gradients, which indicates that alpine plants enhance the NRE to adapt to the increasing droughts and nutrient-poor environments. The opposite trends of N fixation and NRE along the precipitation and soil nutrient gradients indicate that alpine plants adapt to precipitation and soil nutrient limitation by promoting NRE (conservative nutrient use by alpine plants) rather than biological N fixation (open sources by legume plants) on the north Tibetan Plateau.

[Characteristics of soil enzyme stoichiometry along an altitude gradient on Qinghai-Tibet Pla-teau alpine meadow, China]. / é’è—é«˜åŽŸé«˜å¯’è‰ç”¸ä¸åŒæµ·æ‹”åœŸå£¤é ¶åŒ–å­¦è®¡é‡ç‰¹å¾.

Soil enzymes play critical roles in material cycle and energy flow of ecosystems. Understanding soil enzyme activities is of great significance for exploring ecosystem functions. In this study, we investigated soil enzyme activities, stoichiometry and their driving factors at six different altitudes (4300-5100 m) on Qinghai-Tibet Plateau alpine meadow using Biolog microplate analysis. The results showed that ß-1,4-glucosidase (ßG) closely related to C cycle, ß-1,4-N-acetylglucosaminidase (NAG) and L-leucine aminopeptidase (LAP) closely related to N cycle and the activity of acid phosphatase (AP), which was closely related to P cycle, all exhibited unimodal trends with increasing altitude, with the order of 4800 m＞4950 m＞4400 m＞4650 m＞5100 m＞4300 m. Soil N:P enzyme activity ratio showed the same trend as soil enzyme activity, and reached the highest value at 4950 m, however, soil C:N and C:P enzyme activities ratios increased along the altitude. Pearson correlation analysis showed that SOC, TN and soil water content were significantly positively correlated with the activities of four types of enzymes. Mean annual precipitation was significantly negatively associated with the activities of NAG and AP. Mean annual precipitation, mean annual temperature, Shannon diversity, vegetation richness, vegetation coverage and TN affected ratios of soil C:P and N:P enzymes. Soil C:N activity ratio correlated with mean annual temperature, mean annual precipitation, vegetation richness, vegetation coverage, SOC and TN. In summary, soil enzyme activities and stoichiometry had remarkable difference along the altitude gradient on Qinghai-Tibet Plateau alpine meadow, with certain N limitation in high altitude areas. Soil water content, TN, SOC, mean annual precipitation and mean annual temperature were key factors driving such differences.

Different sensitivity and threshold in response to nitrogen addition in four alpine grasslands along a precipitation transect on the Northern Tibetan Plateau.

The increase in atmospheric nitrogen (N) deposition has resulted in some terrestrial ecological changes. In order to identify the response of sensitive indicators to N input and estimate the sensitivity and saturation thresholds in alpine grasslands, we set up a series of multilevel N addition experiments in four types of alpine grasslands (alpine meadow [AM], alpine meadow-steppe [AMS], alpine steppe [AS], and alpine desert-steppe [ADS]) along with a decreasing precipitation gradient from east to west on the Northern Tibetan Plateau. N addition only had significant effects on species diversity in AMS, while had no effects on the other three alpine grasslands. Aboveground biomass of grasses and overall community in ADS were enhanced with increasing N addition, but such effects did not occur in AS. Legume biomass in ADS and AS showed similar unimodal patterns and exhibited a decreasing tend in AM. Regression fitting showed that the most sensitive functional groups were grasses, and the N saturation thresholds were 103, 115, 136, and 156 kg N hm-2 year-1 in AM, AMS, AS, and ADS, respectively. This suggests that alpine grasslands become more and more insensitive to N input with precipitation decrease. N saturation thresholds also negatively correlated with soil N availability. N sensitivity differences caused by precipitation and nutrient availability suggest that alpine grasslands along the precipitation gradient will respond differently to atmospheric N deposition in the future global change scenario. This different sensitivity should also be taken into consideration when using N fertilization to restore degraded grasslands.

Nutrient-induced shifts of dominant species reduce ecosystem stability via increases in species synchrony and population variability.

The mechanisms underlying nutrient-induced diversity-stability relationships have been examined extensively. However, the effects of nutrient-induced shifts of dominant species on ecosystem stability have rarely been evaluated. We compiled a dataset from a long-term nitrogen (N) and phosphorus (P) enrichment experiment conducted in an alpine grassland on the Tibetan Plateau to test the effects of nutrient-induced shifts of dominant species on stability. Our results show that N enrichment increased synchrony among the dominant species, which contributed to a significant increase in synchrony of the whole community. Meanwhile, N-induced shifts in dominant species composition significantly increased population variability. Increases in species synchrony and population variability resulted in a decline in ecosystem stability. Our study has important implications for progress in understanding the role of plant functional compensation in the stability of ecosystem functions, which is critical for better understanding the mechanisms driving both community assembly and ecosystem functions.

Luteolin induces hippocampal neurogenesis in the Ts65Dn mouse model of Down syndrome.

Studies have shown that the natural flavonoid luteolin has neurotrophic activity. In this study, we investigated the effect of luteolin in a mouse model of Down syndrome. Ts65Dn mice, which are frequently used as a model of Down syndrome, were intraperitoneally injected with 10 mg/kg luteolin for 4 consecutive weeks starting at 12 weeks of age. The Morris water maze test was used to evaluate learning and memory abilities, and the novel object recognition test was used to assess recognition memory. Immunohistochemistry was performed for the neural stem cell marker nestin, the astrocyte marker glial fibrillary acidic protein, the immature neuron marker DCX, the mature neuron marker NeuN, and the cell proliferation marker Ki67 in the hippocampal dentate gyrus. Nissl staining was used to observe changes in morphology and to quantify cells in the dentate gyrus. Western blot assay was used to analyze the protein levels of brain-derived neurotrophic factor (BDNF) and phospho-extracellular signal-regulated kinase 1/2 (p-ERK1/2) in the hippocampus. Luteolin improved learning and memory abilities as well as novel object recognition ability, and enhanced the proliferation of neurons in the hippocampal dentate gyrus. Furthermore, luteolin increased expression of nestin and glial fibrillary acidic protein, increased the number of DCX+ neurons in the granular layer and NeuN+ neurons in the subgranular region of the dentate gyrus, and increased the protein levels of BDNF and p-ERK1/2 in the hippocampus. Our findings show that luteolin improves behavioral performance and promotes hippocampal neurogenesis in Ts65Dn mice. Moreover, these effects might be associated with the activation of the BDNF/ERK1/2 pathway.

[Size Distribution and Carbon Component Characteristics of Atmospheric Particulate Matter from Motor Vehicles].

Characterization of the size distribution and carbon components in particulates has become important for identifying the particulates in the atmosphere. The size distribution and carbon components of atmospheric particulate matter from motor vehicles in different regions were analyzed by using Micro-orifice uniform deposition impactors (MOUDI) and the organic carbon/elemental carbon (OC/EC) analyzer. With increasing particle size, the mass concentration of raw diesel/gasoline decreases. The highest mass concentration of particles collected near the chimney of an engine laboratory was observed for particle sizes ranging from 0.32-0.56 µm, while particles with sizes from 1.0-1.8 µm in the basement garage showed the most mass fractions. The OC1, OC2, and OC3 were the major parts of the OC contents in raw diesel particles. The EC2 was the main part of EC. The atmospheric particles collected in typical regions contained more OC3 and OC4. EC1 was the main part of EC in particles collected from the basement garage. The OC/EC ratios of raw diesel particles ranged from 0.92 to 2.50. The OC/EC ratios of particles collected near the chimney of an engine laboratory ranged from 1.40 to 2.53 and that of particles collected in the basement garage ranged from 2.36 to 4.82. Moreover, the OC/EC ratios in particles collected in the basement garage normally exceeded 2.0 and reached 4.82 at the largest size, which implies that many secondary particles were generated in the basement garage. The above-mentioned characteristics provide references that are beneficial for the identification of particulates in the atmosphere originating from motor vehicles.

Emerging role of circadian rhythm in bone remodeling.

The 24-h rhythm of behavioral and physiological processes is a typical biological phenomenon regulated by a group of circadian rhythm genes. Dysfunction of the circadian rhythm can cause a wide range of problems, such as cancer and metabolic diseases. In recent decades, increased understanding of the roles of circadian rhythm genes in the bone remodeling process have been documented, including osteoblastic bone formation, osteoclastic bone resorption, and osteoblast/osteoclast communication. A timely review of the current findings may help to facilitate the new field of circadian rhythmic bone remodeling research. Targeted pharmacological modulation of circadian rhythm genes is a possible therapeutic approach through which to overcome bone remodeling problems in the future.

The effects of warming and nitrogen addition on ecosystem respiration in a Tibetan alpine meadow: The significance of winter warming.

In recent decades, global warming has become an indisputable fact on the Tibetan Plateau. Alpine ecosystems are very sensitive to global warming, and the impact may depend on the degree of atmospheric nitrogen (N) deposition. The previous studies have paid more attention to year-round warming, but the effect of winter warming has been unstudied. In this study, a manipulative experiment was conducted, consisting of warming and N addition. It was carried out since 2010 in an alpine meadow, and three types of warming treatments were set up: no warming (NW), year-round (YW), and winter warming (WW). Warming significantly increased air and soil temperature, but decreased soil moisture. Under no N addition, YW showed significantly decreased ecosystem respiration (Reco) in 2012, and WW decreased Reco in 2014. Under N addition, neither YW nor WW had significant effects on Reco, indicating that N addition compensated the negative effect of warming on Reco. Annually, YW and WW decreased ecosystem carbon (C) emissions, and the extent of the reduction was even larger under WW. Under no N addition, both YW and WW significantly decreased aboveground biomass. Moreover, especially under no N, YW and WW significantly decreased soil inorganic N. WW also had negative effects on soil microbial biomass C. Structure equation modeling showed that soil moisture was the most important factors controlling Reco, and soil inorganic N content and microbial biomass C could explain 46.6% and 16.8% of the variation of Reco. The findings indicate that soil property changes under warming had substantial effects on ecosystem C efflux. The inhibitory effects of winter warming on ecosystem C efflux were mainly attributed to the decline of soil N and microbial biomass. Thus, the effects of winter warming on ecosystem C emissions in this semiarid alpine meadow are not as serious as expected and largely depend on N deposition.

Long Non-coding RNAs: A New Regulatory Code for Osteoporosis.

Osteoporosis is a metabolic bone disease characterized by a decrease in bone mass and degradation of the bone microstructure, which increases bone fragility and fracture risk. However, the molecular mechanisms of osteoporosis remain unclear. Long non-coding RNAs (lncRNAs) have become important epigenetic regulators controlling the expression of genes and affecting multiple biological processes. Accumulating evidence of the involvement of lncRNAs in bone remolding has increased understanding of the molecular mechanisms underlying osteoporosis. This review aims to summarize recent progress in the elucidation of the role of lncRNAs in bone remodeling, and how it contributes to osteoblast and osteoclast function. This knowledge will facilitate the understanding of lncRNA roles in bone biology and shed new light on the modulation and potential treatment of osteoporosis.