The structure and diversity of bacteria and fungi in the roots and rhizosphere soil of three different species of Geodorum.

Shepherd's crook (Geodorum) is a genus of protected orchids that are valuable both medicinally and ornamentally. Geodorum eulophioides (GE) is an endangered and narrowly distributed species, and Geodorum densiflorum (GD) and Geodorum attenuatum (GA) are widespread species. The growth of orchids depend on microorganisms. However, there are few studies on the microbial structure in Geodorum, and little is known about the roles of microorganisms in the endangered mechanism of G. eulophioides. This study analyzed the structure and composition of bacterial and fungal communities in the roots and rhizosphere soil of GE, GD, and GA. The results showed that Delftia, Bordetella and norank_f_Xanthobacteraceae were the dominant bacteria in the roots of Geodorum, while norank_f_Xanthobacteraceae, Gaiella and norank_f_norank_o_Gaiellales were the dominant bacteria in the rhizosphere soil of Geodorum. In the roots, the proportion of Mycobacterium in GD_roadside was higher than that in GD_understory, on the contrary, the proportion of Fusarium, Delftia and Bordetella in GD_roadside was lower than that in GD_understory. Compared with the GD_understory, the roots of GD_roadside had lower microbial diversity. In the endangered species GE, Russula was the primary fungus in the roots and rhizosphere soil, with fungal diversity lower than in the more widespread species. Among the widespread species, the dominant fungal genera in the roots and rhizosphere soil were Neocosmospora, Fusarium and Coprinopsis. This study enhances our understanding of microbial composition and diversity, providing fundamental information for future research on microbial contributions to plant growth and ecosystem function in Geodorum.

Heterologous overexpression of heat shock protein 20 genes of different species of yellow Camellia in Arabidopsis thaliana reveals their roles in high calcium resistance.

Yellow Camellia (Camellia sect. chrysantha) is a rare ornamental plant and an important germplasm resource globally. Camellia nitidissima thrives in normal acidic soils, while Camellia limonia can adapt to the calcareous soils found in karst areas. Our previous study on the karst adaptation of yellow camellias revealed that the expression levels of heat shock protein 20(HSP20) were higher in Camellia limonia than in Camellia nitidissima. However, the functions of the HSP20 gene of Camellia limonia remain unclear to data. In this study, the HSP20 genes of Camellia limonia (ClHSP20-OE lines) and Camellia. nitidissima (CnHSP20-OE lines) were cloned and overexpressed heterologously in Arabidopsis thaliana. Additionally, we overexpressed the HSP20 gene of Arabidopsis (AtHSP20-OE lines) was also overexpressed, and the T-DNA inserted mutants (athspmutant lines) were also used to determine the functions of HSP20 genes. Under high calcium stress, the chlorophyll, nitrogen, water content and humidity of leaves were increased in ClHSP20-OE lines, while those of other lines were declined. The size of the stomatal apertures, stomatal conductance, and the photosynthetic efficiency of ClHSP20-OE lines were higher than those of the other lines. However, the accumulation of H2O2 and O2- in the leaves of ClHSP20-OE lines was the lowest among all the lines. Energy spectrum scanning revealed that the percentage of calcium on the surfaces of the leaves of ClHSP20-OE lines was relatively low, while that of athspmutant lines was the highest. The ClHSP20 gene can also affected soil humidity and the contents of soil nitrogen, phosphorus, and potassium. Transcriptome analysis revealed that the expressions of FBA5 and AT5G10770 in ClHSP20-OE lines was significantly up-regulated compared to that of CnHSP20-OE lines. Compared to that of athspmutant lines, the expressions of DREB1A and AT3G30460 was significantly upregulated in AtHSP20-OE lines, and the expression of POL was down-regulated. Our findings suggest that the HSP20 gene plays a crucial role in maintained photosynthetic rate and normal metabolism by regulating the expression of key genes under high-calcium stress. This study elucidates the mechanisms underlying the karst adaptation in Camellia. limonia and provides novel insights for future research on karst plants.

Can Grassland Rental Lead to Herders' Rotational Grazing Under the Grassland Household Responsibility System? Evidence from Pastoral Areas in Northern China.

Grassland property rights privatization has alleviated the problem of 'the tragedy of the commons' but led to an unintended ecological consequence-traditional nomadic modes declination. However, with the grassland rental market formation in countries with property rights privatization, grassland rental has reshaped the pattern of grassland allocation and provided opportunities for herders to optimize their grazing modes. Based on the survey data of herders in northern China, we theoretically analyze and empirically test grassland rental's impact on herders' rotational grazing behavior under the household responsibility system. The results show that grassland rental promotes herders' rotational grazing, and the probability of individual rotational grazing is increased by 58.27%. By increasing the operated grazing grassland area and the number of grassland plots fenced, grassland rental promotes herders' grassland endowment match with the large-scale livestock activity space and the number of grazing blocks required for rotational grazing, reduces the input cost and operation difficulty required for rotational grazing, and increase herders rotational grazing probability. Grassland rental's impact on herder's rotational grazing is heterogeneous, showing the dependence of the number of plots fenced and the scale of grazing grassland. It has a higher promotion effect on herders with more plots fenced; It cannot promote the generation of herders' rotational grazing behavior when the rented grassland area fails to make the grassland operation scale reach the minimum threshold of rotational grazing. The study emphasizes the importance of developing a grassland rental market to promote the optimization of grazing modes in grassland privatization countries.

Plasmonic coupling-boosted photothermal nanoreactor for efficient solar light-driven photocatalytic water splitting.

Photothermal nanoreactor with rapid charge transfer and improved spectral utilization is a key point in photocatalysis research. Herein, silver sulfide quantum dots (Ag2S QDs) were coating on the surface of porous graphitic carbon nitride nano vesicles (PCNNVs) to form Ag2S/PCNNVs nanoreactors by a simple calcination method for obtaining efficient photothermal-assisted photocatalytic hydrogen (H2) evolution under simulated/real sunlight irradiation. In particularly, the as-prepared optimal 3% Ag2S/PCNNVs sample exhibited the H2 production rate of 34.8 mmol h-1 g-1, which was 3.5 times higher than that of bare PCNNVs. The enhancement of photothermal-assisted activity over the Ag2S/PCNNVs composite system is mainly attributed to the coupling of the photothermal conversion performance of Ag2S QDs and the thermal insulation performance of PCNNVs based on the plasmonic coupling-boosted photothermal nanoreactor. This study presents a promising strategy for the development of high-efficient photothermal-assisted photocatalysts.

Psychological distance and physical distance induced residents' heterogeneous willingness to pay for transboundary watershed ecosystem services in the Wei River Basin, China.

Under the framework of payment for transboundary watershed ecosystem services (ESs), identifying midstream and downstream residents' preference and willingness to pay (WTP) for ESs provided by the upstream is crucial for sustainable watershed management. The residents' preferences and WTP are not evenly distributed within the watershed. This study uses a choice experiment assessing the spatial impact of physical distance (including residents' watershed location and distance to waterbody) and psychological distance on residents' preference and WTP for the Wei River Basin ESs. The results showed that midstream and downstream residents' preference and WTP for the ecological attributes have a significant distance-decay effect, either the physical distance to the upstream exit or physical and psychological distance to the waterbody. However, compared with the residents in the midstream, the residents downstream have a stronger preference and WTP for upstream ecological governance. Besides, the distance-decay effect differs between urban and rural residents. There is a psychological distance-decay effect in rural residents' preference for water quality and a physical distance-decay effect in their preference for water quantity, entertainment area, and cost; there is a physical distance decay effect in urban residents' preference for entertainment areas. The above differences lead to heterogeneity in WTP and total economic value (TEV) for ESs. When calculating the TEV of the transboundary watershed ES and charging the public, policymakers should consider the location of the residents, the physical and psychological distance to the water body, and the difference between urban and rural areas.

Construction of S-Scheme 2D/2D Crystalline Carbon Nitride/BiOIO3 van der Waals Heterojunction for Boosted Photocatalytic Degradation of Antibiotics.

Utilization of semiconductor photocatalyst materials to degrade pollutants for addressing environmental pollution problems has become a research focus in recent years. In this work, a 2D/2D S-scheme crystalline carbon nitride (CCN)/BiOIO3 (BOI) van der Waals heterojunction was successfully constructed for effectively enhancing the degradation efficiency of antibiotic contaminant. The as-synthesized optimal CCN/BOI-3 sample exhibited the highest efficiency of 80% for the photo-degradation of tetracycline (TC, 20 mg/L) after 120 min visible light irradiation, which was significantly higher than that of pure CCN and BOI. The significant improvement in photocatalytic performance is mainly attributed to two aspects: (i) the 2D/2D van der Waals heterojunction can accelerate interface carriers' separation and transfer and afford sufficient active sites; (ii) the S-scheme heterojunction elevated the redox capacity of CCN/BOI, thus providing a driving force for the degradation reaction. The degradation pathways of TC for the CCN/BOI composite were investigated in detail by liquid chromatography-mass spectrometry (LC-MS) analysis. This work provides a design idea for the development of efficient photocatalysts based on the 2D/2D S-scheme van der Waals heterojunctions.

Machine Learning-Based Accurate Analysis of cTnI With Alphalisa Immunoassay Enabled Centrifugal Microfluidic System.

Cardiac troponin (cTnI) is a biomarker with high sensitivity and specificity for acute myocardial infarction (AMI). Rapid and accurate detection of cTnI can effectively reduce the mortality of AMI. Aiming at the problems of complex operation and low sensitivity of traditional methods used to detect cTnI, an Alphalisa immunoassay enabled centrifugal microfluidic system (AIECMS) is designed to detect cTnI quickly with high sensitivity, and good accuracy is achieved in the linear range of 0.1 ng/mL-50 ng/mL. However, in order to realize the detection of hypersensitive cTnI (the definition standard of weak positive and negative is 0.08 ng/mL), it is necessary to further improve the accuracy of qualitative detection. Since the signal curve of the system for reagents of low concentration range is relatively close, the system can not accurately distinguish weak positive and negative samples, which is easy to cause misjudgment of detection results. In order to solve this problem, this paper proposes to apply machine learning to the signal processing detected by AIECMS for the first time. Firstly, different pre-processing is done according to the characteristics of biological signals; Secondly, different machine learning algorithms are used to train and test the data, and the classification of four clinically significant concentrations (0.02 ng/mL, 0.04 ng/mL, 0.08 ng/mL and 0.1 ng/mL) is realized. Finally, combining the performance of various algorithms, algorithm cost and clinical requirements for the accuracy of low concentration classification, we choose random forest (accuracy 92%) to accurately distinguish the weak positive and negative samples of cTnI.

Coupled internal electric field with hydrogen release kinetics for promoted photocatalytic hydrogen production through employing carbon coated transition metal as co-catalyst.

The ideal solution to the energy shortage problem is to split water into hydrogen (H2) utilizing solar-driven semiconductor photocatalytic technology. Nevertheless, severe carrier recombination is the major cause of decreased activity over photocatalysts. Construction of internal electric field (IEF) by coupling semiconductor with metal co-catalyst can effectively promote carrier separation. Herein, Co@C with the Co encapsulated in the C layer as a co-catalyst anchored on the surface of ZnIn2S4 nanosheets via a facile electrostatic self-assembly strategy, achieving outstanding photocatalytic water splitting into H2 under simulated solar irradiation (AM 1.5G) with the production rate of 18.1 mmol h-1 g-1, which is 109.7 times higher than that of bare ZIS without assisted of Pt. Enhancement of photocatalytic H2 evolution activity of Co@C/ZIS is mainly attributed to the construction of giant IEF (4.6-fold higher than ZIS) and suitable environment for hydrogen adsorption and desorption (ΔGH* ∼ 0), which endows the following several advantages: (i) accelerating the migration and separation of photo-generated charges; (ii) improving the hydrogen release kinetics. Our work not only provides a design idea for facile preparation of a high-efficient composite photocatalyst, but also expands the application range of transition metal@carbon as a co-catalyst in energy photocatalysis.

RyhB in Avian Pathogenic Escherichia coli Regulates the Expression of Virulence-Related Genes and Contributes to Meningitis Development in a Mouse Model.

Avian pathogenic Escherichia coli (APEC) is an important member of extraintestinal pathogenic Escherichia coli (ExPEC). It shares similar pathogenic strategies with neonatal meningitis E. coli (NMEC) and may threaten human health due to its potential zoonosis. RyhB is a small non-coding RNA that regulates iron homeostasis in E. coli. However, it is unclear whether RyhB regulates meningitis occurrence. To investigate the function of RyhB in the development of meningitis, we constructed the deletion mutant APEC XM∆ryhB and the complemented mutant APEC XM∆ryhB/pryhB, established a mouse meningitis model and evaluated the role of RyhB in virulence of APEC. The results showed that the deletion of ryhB decreased biofilm formation, adhesion to the brain microvascular endothelial cell line bEnd.3 and serum resistance. RNA-seq data showed that the expression of multiple virulence-related genes changed in the ryhB deletion mutant in the presence of duck serum. Deletion of ryhB reduced the clinical symptoms of mice, such as opisthotonus, diarrhea and neurological signs, when challenged with APEC. Compared with the mice infected with the wild-type APEC, fewer histopathological lesions were observed in the brain of mice infected with the ryhB deletion mutant APEC XM∆ryhB. The bacterial loads in the tissues and the relative expression of cytokines (IL-1ß, IL-6, and TNF-α) in the brain significantly decreased when challenged with the APEC XM∆ryhB. The expressions of tight junction proteins (claudin-5, occludin and ZO-1) were not reduced in the brain of mice infected with APEC XM∆ryhB; that is, the blood-brain barrier permeability of mice was not significantly damaged. In conclusion, RyhB contributes to the pathogenicity of APEC XM in the meningitis-causing process by promoting biofilm formation, adhesion to endothelial cells, serum resistance and virulence-related genes expression.

Surface Hydrophilic Modification for Chip of Centrifugal Microfluidic Immunoassay System.

The surface of a centrifugal microfluidic immunoassay system chip such as polymethyl methacrylate (PMMA) is often hydrophobic, which leads to problems such as poor liquid transfer efficiency and easy-to-block siphon channels, leading to bad fluid control. Therefore, surface hydrophilic modification for such chips is necessary to improve the rapidity and sensitivity of the system. Chemical modification is commonly used, but there is little research on the hydrophilic effect of different concentrations of hydrophilic reagents. According to function requirements for different microchannels of the chip (some only need to ensure the liquid can flow into the next chamber, and some also need to ensure the function of "closing the door" during immunoassay incubation), we explored the best combination of hydrophilic reagent and concentration through experiments. Firstly, three hydrophilic reagents were used for modification. Secondly, the hydrophilic effects of different reagents and concentrations were explored by contact angle test, the influence of different modification methods on liquid transfer efficiency was characterized by residual liquid calculation in the chamber. Finally, the effect of different hydrophilic reagents on absorbance was also tested. By experimental results and comprehensively considering the stability of the modification effect and the function requirements, Tween-20 (2.0% v/v) was chosen as the modifying reagents of the first siphon valve and the second siphon valve, and TritonX-100 (2.0% v/v) was chosen for the third siphon valve, which effectively reduces the contact angle and improves the liquid transfer efficiency, leading to further improvement of the rapidity and sensitivity of the centrifugal microfluidic immunoassay system by efficient siphoning and high plasma separation efficiency (99%).

A lab-on-disc centrifugal microfluidic system for ultraprecise plasma separation.

As the medical community puts forward higher requirements for the speed and convenience of disease diagnosis, point-of-care testing has become a hot research topic to overcome various kinds of healthcare problems. Blood test is considered to be highly sensitive and accurate in clinical diagnosis. However, conventional plasma separation system tends to be bulky and needs professional operations. Moreover, imprecise separation may cause residual biochemical substances such as blood cells to affect the detection results. In this work, to solve these problems, we designed a portable centrifugal microfluidic platform for automatic, rapid and ultraprecise blood separation. The disc consists of multichambers and multi-microchannels where a plasma reservoir and a cell reservoir are connected to each other and collinear with the center of the circle. This structure overcomes the weakness of low separation efficiency (when hematocrit increases) under the traditional blood separation structure (bifurcation structure). As a result, the proposed system achieved 99.9% plasma purity, 99.9% separation efficiency (with a blood hematocrit of 48%) and 32.5% plasma recovery rate in the 50s, which provides a strong guarantee for rapid blood diagnosis and analysis, especially in areas where medical resources are limited.

Well-designed three-dimensional hierarchical hollow tubular g-C3N4/ZnIn2S4 nanosheets heterostructure for achieving efficient visible-light photocatalytic hydrogen evolution.

Photocatalytic water splitting for hydrogen production is an important strategy to achieve clean energy development. In this report, a novel three-dimensional (3D) hierarchical hollow tubular g-C3N4/ZnIn2S4 nanosheets (HTCN/ZIS) type-Ⅱ heterojunction photocatalyst was successfully prepared and applied for photocatalytic hydrogen production under visible light irradiation. The experimental results reveal that the optimal proportion of HTCN/ZIS with the remarkable photocatalytic H2 evolution rate of 20738 µmol h-1 g-1 was obtained. The main reasons for the improvement of hydrogen production activity are as follows: (i) this unique tubular hollow structure can effectively enhances the light capturing ability by the multiple light scattering/reflection of incident light in the inner cavity; (ii) the shorten the phase plane transmission distance could reduce the path of charge transfer; (iii) the surface coated a large number of scaly ZnIn2S4 nanosheets can provide abundant reactive sites. Combining the various characterization tests, the enhanced spatial segregation of charge carriers could owning to the intimately interfacial contact and well-matched band gaps structure between g-C3N4 and ZnIn2S4 through the type-II heterojunction. This work provides a new prospect for the construction of a novel 3D hierarchical type-II heterojunction photocatalyst for highly efficient photocatalytic hydrogen production.

Application of centrifugal microfluidics in immunoassay, biochemical analysis and molecular diagnosis.

Rapid diagnosis plays a vital role in daily life and is effective in reducing treatment costs and increasing curability, especially in remote areas with limited availability of resources. Among the various common methods of rapid diagnosis, centrifugal microfluidics has many unique advantages, such as less sample consumption, more precise valve control for sequential loading of samples, and accurately separated module design in a microfluidic network to minimize cross-contamination. Therefore, in recent years, centrifugal microfluidics has been extensively researched, and it has been found to play important roles in biology, chemistry, and medicine. Here, we review the latest developments in centrifugal microfluidic platforms in immunoassays, biochemical analyses, and molecular diagnosis, in recent years. In immunoassays, we focus on the application of enzyme-linked immunosorbent assay (ELISA); in biochemical analysis, we introduce the application of plasma and blood cell separation; and in molecular diagnosis, we highlight the application of nucleic acid amplification tests. Additionally, we discuss the characteristics of the methods under each platform as well as the enhancement of the corresponding performance parameters, such as the limit of detection, separation efficiency, etc. Finally, we discuss the limitations associated with the existing applications and potential breakthroughs that can be achieved in this field in the future.

Formation of unique hollow ZnSnO3@ZnIn2S4 core-shell heterojunction to boost visible-light-driven photocatalytic water splitting for hydrogen production.

Herein, it is reported that a batch of hollow core-shell heterostructure photocatalysts were carefully fabricated using a reliable and convenient low-temperature solvothermal method, and ultra-thin ZnIn2S4 nanosheets are grown in situ on the hollow ZnSnO3 cubes to achieve efficient photocatalytic hydrogen evolution. This unique layered hollow structure utilizes multiple light scattering/reflection within the cavity to enhance light absorption, the thin shell reduces the path of charge transfer, and the irregular nanosheets-wrapped outer layer not only enhances the adsorption power, but also provides an abundant active sites to promote the efficiency of photocatalytic water splitting to produce hydrogen. Therefore, due to the matching energy band and unique structure, the ZnSnO3@ZnIn2S4 hollow core-shell heterostructure photocatalyst exhibits superior H2 production efficiency (16340.18 µmol h-1 g-1) and outstanding stability. This work emphasizes the importance of carefully designing a suitable material structure in addition to adjusting the chemical composition.

Effects of social interactions and information bias on the willingness to pay for transboundary basin ecosystem services.

Payments for watershed ecosystem services are the most important forms of global water environmental protection. Transboundary basin ecological compensation policies in China are mainly based on the central government's appropriation to local governments or transfer payments between local governments. However, watershed ecosystem services face many problems such as the lack of interprovincial horizontal compensation policies and insufficient public participation. Most of China's rivers are distributed in vast rural areas, and the livelihoods of farmers living in these areas are highly dependent on the water environment. Since a watershed usually spans multiple administrative regions, the inconsistency between the natural and administrative boundaries of the river affects the completeness of the ecosystem services' information exchange between the service providers and payers. To promote interprovincial government water management cooperation and spark the farmers' enthusiasm for participating in the payments for watershed ecosystem services, this study examines the mechanism by which social interactions can affect farmers' willingness to pay (WTP) by mitigating the information bias. The results show that information bias plays a mediating role in the effect of social interactions on WTP. Additionally, the cadres/associations' and village-level interactions can effectively reduce the information bias of farmers, thereby increasing their WTP for transboundary basin ecosystem services. Moreover, the intensity of the psychological ownership of the watershed and government credibility have a significant moderating effect on the above-mentioned mechanisms. This study suggests that it is necessary to broaden the source channels of farmers' information on upstream ecological governance, improve the completeness of farmers' information, and curb the negative impact of information bias on WTP. Simultaneously, it is necessary to improve the government credibility and cultivate the farmers' sense of belonging and responsibility toward the watershed.

Application of Microfluidics in Immunoassay: Recent Advancements.

In recent years, point-of-care testing has played an important role in immunoassay, biochemical analysis, and molecular diagnosis, especially in low-resource settings. Among various point-of-care-testing platforms, microfluidic chips have many outstanding advantages. Microfluidic chip applies the technology of miniaturizing conventional laboratory which enables the whole biochemical process including reagent loading, reaction, separation, and detection on the microchip. As a result, microfluidic platform has become a hotspot of research in the fields of food safety, health care, and environmental monitoring in the past few decades. Here, the state-of-the-art application of microfluidics in immunoassay in the past decade will be reviewed. According to different driving forces of fluid, microfluidic platform is divided into two parts: passive manipulation and active manipulation. In passive manipulation, we focus on the capillary-driven microfluidics, while in active manipulation, we introduce pressure microfluidics, centrifugal microfluidics, electric microfluidics, optofluidics, magnetic microfluidics, and digital microfluidics. Additionally, within the introduction of each platform, innovation of the methods used and their corresponding performance improvement will be discussed. Ultimately, the shortcomings of different platforms and approaches for improvement will be proposed.

Research on the impact of agricultural green production on farmers' technical efficiency: evidence from China.

Agricultural green production (AGP) and efficiency improvement of smallholders' management are the objective requirements for the development of China's modernized agriculture and the understanding of the rural vitalization strategy. Based on field survey data of 582 rice farmers in Shaanxi Province, this study used the Logit model to analyze the determinants of smallholders' adoption of agricultural green production technology (AGPT) and used the propensity score matching (PSM) method to measure the effect of AGPT on the technical efficiency (TE) of rice production and the heterogeneity of this influence among smallholders. Results showed that the AGPT adoption rate and the mean of rice production TE were 15.1% and 0.312, both had a lot of room for improvement. Furthermore, it was found that household's characteristics, family characteristics, agricultural management characteristics, social characteristics, and cognitive characteristics significantly affect smallholders' AGPT adoption, and the AGPT adoption significantly increased the TE of rice production by 18.8 to 24.5%. Besides, farmers with older age, less education, more specialized planting, more fragmented land, and more off-farm employment adopting AGPT could significantly improve the TE; the increase proportion was 29.8%, 29.5%, 21.3%, 27.2%, and 16.8%. The study also showed that the AGPT could not significantly increase the rice output value of smallholders. In addition, considering the endogeneity problem caused by sample selection bias, the study re-estimated using the endogenous transformation regression (ESR) model which showed that the promotion of AGPT to TE was still robust. The study puts forward policy recommendations on how to further promote the adoption of AGPT and improve the TE by farmers.

Assessing restoration benefit of grassland ecosystem incorporating preference heterogeneity empirical data from Inner Mongolia Autonomous Region.

The evaluation of grassland ecosystem restoration benefit considering herdsmen's preference is an important reference for the formulation of grassland protection policy. This study aims to evaluate the marginal benefits of grassland ecosystem services by using choice experiment and mixed logit (ML) model, and a latent class model (LCM) is estimated to identify and explain the heterogeneity of herdsmen's preference for the various functions of the grassland ecosystem, so as to estimate the benefits of grassland ecosystem restoration in Siziwang Banner and Damao Banner of Inner Mongolia Autonomous Region. The results reveal that the restoration benefit of the grassland ecosystem in the two banners is nearly 341.1 million RMB per year. The application of latent class model highlights three potential segments of the herdsmen with different preferences. The social, economic and environmental attitudinal characteristics of herdsmen have significant impacts on their preferences. Thus, to improve the universality of grassland ecological restoration policy, herdsmen's preferences should be thoroughly investigated before policy formulation and implementation. Meanwhile, it is important to publicize the grassland ecosystem services, to popularize the role of wildlife in the ecosystem, and to realize the benign interaction between wildlife protection and animal husbandry development.

Effects of p-glycoprotein on steroid-induced osteonecrosis of the femoral head.

P-glycoprotein (P-gp) activity may play an important role in steroid-induced osteonecrosis of the femoral head (ONF); however, the precise mechanism of its pathogenesis remains unknown. Therefore, we investigated the effects of increased P-gp activity on steroid-induced ONF using a rat model. Rats (n = 60) were treated with either a pharmacological stimulant of P-gp, rifampicin (group A); a suppressant, verapamil (group B); or normal saline (group C) administered in conjunction with methylprednisolone, an inducer of ONF. P-gp activity in bone marrow cells and expression in the femoral head significantly increased in group A (P < 0.05) but decreased in group B (P < 0.05). Likewise, the serum osteocalcin level, trabecular thickness and number, osteoclast and osteoblast numbers, and mean percentage of the epiphyseal ossification center were significantly increased in group A (P < 0.01) but decreased in group B (P < 0.01). In contrast, however, adipocytic variables, trabecular separation, and apoptotic cells decreased in group A (P < 0.01) but increased in group B (P < 0.01). The ONF incidence in group A (50%) and group B (100%) was significantly different from that in the control group C (80%, P < 0.05). Taken together, our findings suggested that enhanced P-gp activity was able to decrease the risk of steroid-induced ONF, possibly by inhibiting adipogenesis and apoptosis in the femoral head.

Effect of rifampicin on the risk of steroid-induced osteonecrosis of the femoral head.

OBJECTIVE: To investigate the effects and possible mechanism of rifampicin on steroid-induced osteonecrosis of the femoral head (ONFH). METHODS: Bone marrow stromal cells (BMSC) separated from male rats were cultured in vitro without any treatment (Group mA), exposed to dexamethasone (Group mB), treated with rifampicin (Group mC), and exposed to dexamethasone and rifampicin simultaneously (Group mD) respectively (n = 5 in each group). After 7 days, P-glycoprotein (P-gp) activity and adipogenesis of the BMSC were evaluated. In an in vivo experiment, 80 rats were randomly divided into 4 groups (n= 20 in each group). Group A received intragastric saline for 5 weeks. Group B received intragastric saline for one week, followed by subcutaneous methylprednisolone and saline for 4 weeks. Group C received intragastric rifampicin for 5 weeks. Group D received intragastric rifampicin for one week, followed by subcutaneous methylprednisolone and rifampicin for 4 weeks. At the end of the experiment, all rats underwent analysis of P-gp activity of BMSC, P-gp expression in the femoral heads, MRI and histomorphometry of the femoral heads. RESULTS: In vitro, the P-gp activity of BMSC increased and lipid accumulation decreased significantly in Group mD, compared to Group mB. In vivo, P-gp activity and P-gp expression in Group D increased compared to Group B. The mean area of MRI abnormal signal, adipocytic variables and apoptotic cells in Group D decreased, mean percentage of the whole epiphysis made up by the epiphyseal ossification center and trabecular structure variables improved compared to those in Group B. The incidence of ONFH was lower in Group D (50%) than in Group B (80%). CONCLUSION: Rifampicin may decrease the risk of steroid-induced ONFH by enhancing P-gp activity, thus preventing steroid-induced BMSC adipogenesis.