Responses of soil fungal community to the sandy grassland restoration in Horqin Sandy Land, northern China.

Sandy grassland restoration is a vital process including re-structure of soils, restoration of vegetation, and soil functioning in arid and semi-arid regions. Soil fungal community is a complex and critical component of soil functioning and ecological balance due to its roles in organic matter decomposition and nutrient cycling following sandy grassland restoration. In this study, soil fungal community and its relationship with environmental factors were examined along a habitat gradient of sandy grassland restoration: mobile dunes (MD), semi-fixed dunes (SFD), fixed dunes (FD), and grassland (G). It was found that species abundance, richness, and diversity of fungal community increased along with the sandy grassland restoration. The sequences analysis suggested that most of the fungal species (68.4 %) belonged to the phylum of Ascomycota. The three predominant fungal species were Pleospora herbarum, Wickerhamomyces anomalus, and Deconica Montana, accounting for more than one fourth of all the 38 species. Geranomyces variabilis was the subdominant species in MD, Pseudogymnoascus destructans and Mortierella alpine were the subdominant species in SFD, and P. destructans and Fungi incertae sedis were the dominant species in FD and G. The result from redundancy analysis (RDA) and stepwise regression analysis indicated that the vegetation characteristics and soil properties explain a significant proportion of the variation in the fungal community, and aboveground biomass and C:N ratio are the key factors to determine soil fungal community composition during sandy grassland restoration. It was suggested that the restoration of sandy grassland combined with vegetation and soil properties improved the soil fungal diversity. Also, the dominant species was found to be alternative following the restoration of sandy grassland ecosystems.

Mapping Chinese annual gross primary productivity with eddy covariance measurements and machine learning.

Annual gross primary productivity (AGPP) is the basis for grain production and terrestrial carbon sequestration. Mapping regional AGPP from site measurements provides methodological support for analysing AGPP spatiotemporal variations thereby ensures regional food security and mitigates climate change. Based on 641 site-year eddy covariance measuring AGPP from China, we built an AGPP mapping scheme based on its formation and selected the optimal mapping way, which was conducted through analysing the predicting performances of divergent mapping tools, variable combinations, and mapping approaches in predicting observed AGPP variations. The reasonability of the selected optimal scheme was confirmed by assessing the consistency between its generating AGPP and previous products in spatiotemporal variations and total amount. Random forest regression tree explained 85 % of observed AGPP variations, outperforming other machine learning algorithms and classical statistical methods. Variable combinations containing climate, soil, and biological factors showed superior performance to other variable combinations. Mapping AGPP through predicting AGPP per leaf area (PAGPP) explained 86 % of AGPP variations, which was superior to other approaches. The optimal scheme was thus using a random forest regression tree, combining climate, soil, and biological variables, and predicting PAGPP. The optimal scheme generating AGPP of Chinese terrestrial ecosystems decreased from southeast to northwest, which was highly consistent with previous products. The interannual trend and interannual variation of our generating AGPP showed a decreasing trend from east to west and from southeast to northwest, respectively, which was consistent with data-oriented products. The mean total amount of generated AGPP was 7.03 ± 0.45 PgC yr-1 falling into the range of previous works. Considering the consistency between the generated AGPP and previous products, our optimal mapping way was suitable for mapping AGPP from site measurements. Our results provided a methodological support for mapping regional AGPP and other fluxes.

Electrical properties and behaviors of cuprous oxide cubes under high pressure.

An accurate in situ electrical resistivity measurement of cuprous oxide cubes has been conducted in a diamond anvil cell at room temperature with pressures up to 25 GPa. The abnormal electrical resistivity variation found at 0.7-2.2 GPa is attributed to the phase transformation from a cubic to a tetragonal structure. Three other discontinuous changes in the electrical resistivity are observed around 8.5, 10.3, and 21.6 GPa, corresponding to the phase transitions from tetragonal to pseudocubic to hexagonal to another hexagonal phase, respectively. The first-principles calculations illustrate that the electrical resistivity decrease of the tetragonal phase is not related to band-gap shrinkage but related to a higher quantity of electrons excited from strain-induced states increasing in band gap with increasing pressure. The results indicate that the Cu(2)O cubes begin to crush at about 15 GPa and completely transform into nanocrystalline at 25 GPa.

[Theoretical basis of ecology for the influence of global change on resources, environment, and ecosystems.] / å ¨çƒå˜åŒ–å¯¹èµ„æºçŽ¯å¢ƒåŠç”Ÿæ€ç³»ç»Ÿå½±å“çš„ç”Ÿæ€å­¦ç†è®ºåŸºç¡€.

With the deepening of global change research, the applied problems such as global change risk and response for social sustainable development, temporal and spatial allocation of resources and environmental elements and impact assessment of ecosystem are becoming a new trend in the research field of global change. Based on the ecological framework, we focused on clarifying the connotations of resources and the environment and their components. Resources refer to all substances consumed by organisms in the process of producing organic matter from inorganic matter and transferring energy and matter among organisms. These include inorganic resources (e.g., solar radiation, CO2, O2, water, and mineral elements) and organic resources (as a source of food for other organisms). In contrast, the environment can not be consumed or depleted by organisms. In addition, we described the components of global change and the associated variations of resources and environmental factors, as well as current research progress on the responses of ecosystem to global change. We scientifically described the processes and mechanisms of global change in terms of their influence on resources, the environment, and ecosystems within a theoretical framework based on ecological principles. Our goal was to provide a strong theoretical foundation for future research on coping with the risks of global change.

[Soil stoichiometry characteristics under different land use types in the Horqin Sandy Land, China]. / 科尔沁沙地不同土地利用类型土壤化学计量特征.

The stoichiometry characteristics of carbon (C), nitrogen (N), and phosphorus (P) is an important indicator of soil quality and ecosystem nutrient limitations. Exploring the effects of land use type and soil depth on soil nutrient stoichiometry can clarify soil nutrient cycling. In this study, we collected soil samples from sites with five different land use types (irrigated cropland, rainfed cropland, sandy grassland, fixed dunes, and mobile dunes) in the Horqin Sandy Land, and evaluated the influences of land use type and soil depth on the contents and stoichiometry characteristics of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP). We found that: 1) SOC (3.23 g·kg-1), TN (0.37 g·kg-1), and TP (0.15 g·kg-1) contents and stoichiometry characteristics (C:N, C:P, N:P was 9.07, 25.56, 2.97, respectively) to a depth of 10 cm in the Horqin Sandy Land were significantly lower than the mean values of soils in China. 2) Soil stoichiometry characteristics differed significantly among land use types. The contents of SOC, TN, and TP to a depth of 100 cm were highest in irrigated cropland, followed by sandy grassland, rainfed cropland, fixed dunes, and mobile dunes. The C:N ratios in sandy grassland, irrigated cropland, and rainfed cropland were significantly higher than those in the fixed dune and mobile dune sites. C:P ratios in the sandy grassland, fixed dunes, irrigated cropland, and rainfed cropland were significantly higher than that in the mobile dunes. The N:P ratio differed little among the five land use types. 3) SOC and TN contents in the sandy grassland, fixed dunes, irrigated cropland, and rainfed cropland decreased with increasing soil depth. SOC, TN, and C:P in the mobile dunes and TP and C:N in all land use types showed no variation among depths. The C:P ratio of sandy grassland, fixed dunes, irrigated cropland, and rainfed cropland and the N:P ratio of sandy grassland decreased with increasing soil depth. 4) SOC, TN, and TP contents and the C:N ratio were significantly negatively correlated with the contents of medium and fine sands and with soil bulk density, but significantly positively correlated with silt+clay, and very fine sand contents. Desertification led to losses of SOC and nutrients in the Horqin Sandy Land, and exacerbated soil N deficiency. Inputs of water and ferti-lizer helped cropland to maintain a relatively high level of soil nutrients.

Resolving the origins of invertebrate colonists in the Yangtze River Estuary with molecular markers: Implications for ecological connectivity.

Understanding connectivity over different spatial and temporal scales is fundamental for managing of ecological systems. However, controversy exists for wintertime ecological connectivity between the Yangtze River Estuary (YRE) and inner southwestern Yellow Sea. Here, we investigated ecological connectivity between the YRE and inner southwestern Yellow Sea in wintertime by precisely pinpointing the source of the newly colonized populations of a winter-spawning rocky intertidal invertebrate, Littorina brevicula (Philippi, 1844), on artificial structures along the coast of the Yangtze River Delta (YRD) using mitochondrial ND6 sequences and microsatellite data. Clear phylogeographic and genetic differentiation were detected between natural rocky populations south and north of the YRE, which resulted from the lack of hard substrate for rocky invertebrates in the large YRD coast. For the newly colonized populations on the coast of YRD, most individuals (98%) to the south of ~33.5°N were from natural rocky populations to the south of the YRE and most of those (94%) to the north of ~33.5°N were from the northern natural rocky populations, which demonstrated strong ecological connectivity between the inner southwestern Yellow Sea and the YRE in winter time. We presented the first genetic evidence that demonstrated a northward wintertime coastal current in the inner southwestern Yellow Sea, and precisely illustrated the boundary of the coastal current recently proposed by numerical experiment. These results indicated that the YRE serves as an important source of materials and energy for the inner southwestern Yellow Sea in winter, which can be crucial for the function of the Yellow Sea ecosystem.

[Extracts of mucopolysaccharides from Asterias rollestoni and its immunoregulation effect in vitro].

OBJECTIVE: To study immunoregulation effects on normal pulpal cells of the mucopolysaccharides MP1 and MP2 extracted from Asterias rollestoni body wall and viscera, respectively. METHODS: The orthogonal design was employed to obtain the best possible combination of the critical parameters for mucopolysaccharide MP2. MP1, MP2, glycosides, MP1 + glycosides and MP2 + glycosides were added respectively into pulpal cells culture media to test their effects on spleen cells proliferations by MTT assay. RESULTS: MP1 and MP2 could certainly increase the proliferation of the normal splenocyte and inhibit glycosides cytotoxicity. Compared with controls, MP2 reversed the cytotoxicity of glycosides at concentration of 25 to 40 mg/mL, the greatest activity appearing at the dose of 40 mg/mL (P<0.01), while MP1 didn't reverse it. CONCLUSION: MP1 and MP2 can enhance immunity of normal mice, and MP2 can significantly reverses the cytotoxicity of glycosides in vitro.

Exploring Confluence-Related Signalling to Modulate the Expression of Oct4 - A Role in Facilitating Mouse Somatic Cell Reprogramming?

Oct4 is uniformly expressed by all types of pluripotent cells and is essential for pluripotency. Oct4 is also the central reprogramming factor that is constant in most transcription factor cocktails used to generate iPS cells. This article discusses the mechanisms of regulating Oct4 expression by confluence-based Hgf and hypoxia signalling in mouse somatic cells. Stat3 is activated ligandindependently in confluent cells and triggers the formation of cell aggregates. Hgf signalling is preserved after confluence, stimulating ß-catenin and Stat3 activity, which are both crucial for Oct4 transcription. Stat3 and ß-catenin activities also help sustain cell survival and proliferation, resulting in the formation of cell spheres. Hypoxic conditions in spheres activate regulators of Oct4 and further induce Oct4 expression. Activation of the Oct4 gene depends on nuclear receptors Lrh1/SF1, Esrrb, and Rars. These interact synergistically to initiate Oct4 transcription through organizing a transcriptional initiation complex. cAMP signalling stimulates the production of the SF1/Lrh1 ligand. Esrrb agonist or estrogen might function in activating Esrrb, while Rars might be induced by hypoxia. Taken together, Oct4 expression is probably induced in mouse somatic cells by culturing post-confluence cells with media containing Hgf, Esrrb agonist, and cAMP agonist. Exploring confluence-related signalling to modulate the expression of Oct4 might be helpful in finding novel strategies for reprogramming somatic cells.

[Inter- and intra-annual dynamics of vegetation litter at different habitats in Horqin Sandy Land, China.] / ç§‘å°”æ²æ²™åœ°ä¸åŒç”Ÿå¢ƒæ¤è¢«å‡‹è½ç‰©å¹´é™ åŠå¹´å† åŠ¨æ€.

As one of the important pathways of material and energy flow between plant and soil system, litterfall plays a key role in the process of vegetation and soil restoration in ecologically fragile region. To explore the inter- and intra-annual dynamics of litter production and related regulatory factors at different habitats in sandy land ecosystem, we investigated the litter production during nine continuous growing seasons, while the air temperature and precipitation were measured over mobile dune, fixed dune, and grassland in Horqin Sandy Land. The results showed that annual litter production at different habitants were in the order of mobile dune (9.01 g·m-2) ＜ fixed dune (67.46 g·m-2) ＜ grassland (119.55 g·m-2). The inter-annual dynamics of litterfall fluctuated significantly, with a double-peak curve in fixed dune and "W" curve in grassland. The intra-annual variation of litterfall exhibited a "U" curve at all the three habitats, with peaks appearing in April and September, respectively. Precipitation and temperature had significant effects on the intra-annul dynamics of litterfall production in fixed sand dune and grassland, but had no significant effect on the inter-annual dynamics of litter production at three habitats. Temperature was the major factor affecting the dynamics of the litter fall during the growing season in Horqin Sandy Land.

Networks of Transcription Factors for Oct4 Expression in Mice.

The present review aimed to assess the networks of transcription factors regulating the Oct4 expression in mice. Through a comprehensive analysis of the binding sites and the interrelationships of the transcription factors of Oct4, it is found that transcription factors of Oct4 form three regulating complexes centered by Oct4-Sox2, Nanog, and Lrh1. They bind on CR4, CR2, and CR1 regions of Oct4 promoter/enhancer, respectively, to activate Oct4 transcription synergistically. This article also discusses the mechanisms of fine-tuning the Oct4 expression. These findings have important implications in the field of stem cell and developmental biology.

Increased pollinator service and reduced pollen limitation in the fixed dune populations of a desert shrub.

Evaluations of restoration success usually focus on the structural aspects of ecosystems. Pollination, as an important functional aspect, is often overlooked. Here, the shifts in pollinator assemblage and pollen limitation in the desert shrub Caragana microphylla were examined along a restoration gradient in Horqin Sand Land, northern China. We identified seven species of bees; however, only four bee species were found to be effective pollinators, with Xanthosaurus remota dominating in the fixed dunes, and with no bee species or only a single species, X. remota, being observed in the semi-fixed and mobile dunes. Flower visitation rate was nearly ten times higher in the fixed dunes than in the mobile and semi-fixed dunes. Experimental floral manipulations revealed that the fixed dune populations experienced less pollen limitation, along with the increase in pollinator availability. Between the mobile and semi-fixed dune populations, pollen limitation was severe and at similar levels. The intensity of pollen limitation was negatively related to pollinator abundance and richness. Overall, the dependence on pollinators for reproduction may be an important constraint that limits persistence in this system. Increased pollinator service during the restoration process may ameliorate pollen limitation, benefiting the restoration of vegetation in this semiarid sandy area.

Earlier flowering did not alter pollen limitation in an early flowering shrub under short-term experimental warming.

In animal pollinated plants, phenological shifts caused by climate change may have important ecological consequences. However, no empirical evidence exists at present on the consequences that flowering phenology shifts have on the strength of pollen limitation under experimental warming. Here, we investigated the effects of experimental warming on flowering phenology, flower density, reproductive success, and pollen limitation intensity in Caragana microphylla and evaluated whether earlier flowering phenology affected plant reproduction and the level of pollen limitation using warmed and unwarmed open top chambers in the Horqin Sandy Land of Inner Mongolia, northern China. The results of this study indicated that artificial warming markedly advanced flower phenology rather than extending the duration of the flowering. Additionally, warming was found to significantly reduce flower density which led to seed production reduction, since there were insignificant effects observed on fruit set and seed number per fruit. Experimental floral manipulations showed that warming did not affect pollen limitation. These results revealed the negative effects of advanced phenology induced by warming on flower density and reproductive output, as well as the neutral effects on reproductive success and pollen limitation intensity of long surviving plants.

Inhibition of SW620 human colon cancer cells by upregulating miRNA-145.

AIM: To investigate the targeted inhibition of proliferation and migration of SW620 human colon cancer cells by upregulating miRNA-145 (miR-145). METHODS: Forty-five samples of colon cancer tissues and 45 normal control samples were obtained from the biological database of the First Affiliated Hospital of Liaoning Medical University. We performed quantitative analysis of miR-145 and N-ras expression in tissues; reverse transcriptase polymerase chain reaction analysis of miR-145 expression in SW620 colon cancer cells and normal colonic epithelial cells; construction of miR-145 lentiviral vector and determination of miR-145 expression in SW620 cells transduced with miR-145 vector; analysis of the effect of miR-145 overexpression on SW620 cell proliferation; analysis of the effect of miR-145 overexpression on SW620 cell migration using a wound healing assay; and analysis of the effect of miR-145 on N-ras expression using Western blotting. RESULTS: miR-145 expression was significantly downregulated in colon cancer tissues, with its expression in normal colonic tissues being 4-5-fold higher (two sample t test, P < 0.05), whereas N-ras expression showed the opposite trend. miR-145 expression in SW620 cells was downregulated, which was significantly lower compared to that in colonic epithelial cells (two sample t test, P < 0.05). miR-145 vector and control were successfully packaged; expression of miR-145 in SW620 cells transduced with miR-145 was 8.2-fold of that in control cells (two sample t test, P < 0.05). The proliferation of miR-145-transduced SW620 cells was significantly decreased compared to control cells (two sample t test, P < 0.05). At 48 h in the wound healing experiment, the migration indexes and controls were (97.27% ± 9.25%) and (70.22% ± 6.53%), respectively (two sample t test, P < 0.05). N-ras expression in miR-145-tranduced SW620 cells was significantly lower than others (one-way analysis of variance, P < 0.05). CONCLUSION: miR-145 is important in inhibiting colon cancer cell proliferation and migration. This is a good foundation for development of colon cancer therapy by targeting tumor suppressor miR-145.

[Germination and seedling growth of Artemisia halodendron under different incubation environments].

Artemisia halodendron is a dominant species in mobile and semi-mobile dunes of Horqin Sand Land. To investigate the germination character and seedling growth under different temperature and light conditions, the germination rate, germination index and growth of radicle and plumule were measured after treatments in laboratory and heating cabinet incubations. In the laboratory the light and temperature were near to nature condition, while in the heating cabinet it was kept at 25 degrees C with varying durations of light supply, including 24-, 12- and 0-hour light per day. Germination rate (66.6%) and germination index (19.1%) under laboratory condition were both significantly lower than in the heating cabinet (P < 0.05). In the heating cabinet, the germination rate under 0-hour light was 70.2%, which was insignificantly lower (P > 0.05) than under 12- and 24-hour light conditions (both 73.4%), and the germination index under 24-hour light was 28.2%, which was significantly (P < 0.05) lower than under 0- and 12-hour light conditions (31.3% and 30.8%, respectively). Radicle and plumule growth responded to light more readily than the seed germination rate and germination index during the process of germination, and the radicle growth was inhibited by darkness while promoted by light, and the plumule lengths under 0- and 12-hour light conditions were 2.81 cm and 1.51 cm, respectively, significantly higher than under 24-hour light (1.21 cm) and natural condition (1.27 cm). It was concluded that temperature was a main factor in seed germination, and seedling growth was mainly influenced by light regime.

Purification and structural characterization of a new water-soluble neutral polysaccharide GLP-F1-1 from Ganoderma lucidum.

A water-soluble neutral polysaccharide (GLP-F1-1) was isolated from the fruiting bodies of Ganoderma lucidum by DEAE Sepharose Fast Flow and Sephacryl S-500 High Resolution Chromatography. The neutral polysaccharide had an average molecular weight (Mw) of approximately 2.5×10(6) kDa. GC analysis showed that this polysaccharide was mainly composed of glucose and galactose in the molar ratio of 34:1. 1H and 13C NMR spectroscopy in combination with GC-MS technique indicated that the new polysaccharide had a backbone chain of 1,4-disubstituted-ß-glucoseopyranose and 1,4,6-trisubstituted-ß-glucoseopyranosyl, while the branched chains were mainly composed of 1,6-disubstituted-ß-glucopyranosyl and 1,4-disubstituted-ß-galactoseopyranosyl residues.

[Dynamic changes of surface soil organic carbon and light-fraction organic carbon after mobile dune afforestation with Mongolian pine in Horqin Sandy Land].

This paper studied the dynamic changes of surface (0-15 cm) soil organic carbon (SOC) and light-fraction organic carbon (LFOC) in 25- and 35-year-old sand-fixing Mongolian pine (Pinus sylvestris var. mongolica) plantations in Horqin Sandy Land, with a mobile dune as a comparison site. After the afforestation on mobile dune, the content of coarse sand in soil decreased, while that of fine sand and clay-silt increased significantly. The SOC and LFOC contents also increased significantly, but tended to decrease with increasing soil depth. Afforestation increased the storages of SOC and LFOC in surface soil, and the increment increased with plantation age. In the two plantations, the increment of surface soil LFOC storage was much higher than that of SOC storage, suggesting that mobile dune afforestation had a larger effect on surface soil LFOC than on SOC.

Master stem cell transcription factors and signaling regulation.

The present article reviews master stem cell transcription factors, their expression regulation network, and related signaling pathways with the aim of understanding the molecular mechanisms of pluripotent cell fate decisions. Oct4, Sox2, and Nanog are master transcription factors for maintenance of the undifferentiated state and self-renewal of embryonic stem cells (ESCs). In the mouse, they form a regulatory circuitry with coregulators, such as beta-catenin, Stat3, Myc, Klfs, Sall4, and Esrrb to control the expression of pluripotency-related genes including themselves. The threshold expression of Oct4, Sox2, and Nanog for sustaining ESC properties depends on the synergistic effects among Stat3, beta-catenin, and Smad signaling pathway under the specific conditions of the ESC cytoplasmic microenvironment. Some of the salient differences in human ESC signaling pathways affecting their fate commitment are highlighted.

High-efficiency continuous-wave Raman conversion with a BaWO(4) Raman crystal.

We report a high-efficiency cw Raman conversion with a BaWO(4) Raman crystal in a diode-end-pumped Nd:YVO(4) laser. The Raman threshold is as low as 3.6 W of diode power at 808 nm. The highest output power obtained at the 1,180 nm first-order Stokes line is 3.36 W under the diode power of 25.5 W, corresponding to a slope efficiency of 15.3% and a diode-to-Stokes optical conversion efficiency of 13.2%. The intracavity Raman conversion efficiency is 21.5% with respect to the available output of the 1,064 nm fundamental.

[Soil condensation water in different habitats in Horqin sandy land: an experimental study].

Weighing method was adopted to study the formation time and the amount of soil condensation water in four habitats (mobile sandy land, fixed sandy land, farmland, and Mongolian pine forest land) in Horqin Sandy Land in August 2007. The soil condensation water began to form at 20:00-22:00, increased gradually at 22:00-4:00, and began to evaporate after 4:00. In the four habitats, soil condensation water was mainly formed in 0-9 cm layer, and the amount was the greatest in 0-3 cm layer, accounting for 40% of the total. The soil condensation water also formed in 9-30 cm layer, but in very small amount. There was a greater difference in the mean daily amount of soil condensation water in 0-3 cm layer in the four habitats, with the sequence of fixed sandy land > mobile sandy land > farmland > Mongolian pine forest land, which indicated that the habitat with better vegetation condition was not benefit the formation of soil condensation water. The mean daily amount of soil condensation water in 0-30 cm layer was 0.172 mm in fixed sandy land, 0.128 mm in Mongolian pine forest land, 0.120 mm in mobile sandy land, and 0.110 mm in farmland.

[Research progress on wind erosion control].

Wind erosion is the main inducement and an important process of desertification, and also, a main environmental problem needed to be controlled in many countries and areas. Based on the formation mechanisms of wind erosion and some important research results, this paper reviewed the biological, chemical, and mechanical measures in wind erosion control, which could be applied individually or integrated together to decrease or prevent wind erosion. It was suggested that management should be strengthened to ensure a better effect in applying these measures to further improve ecological environment.