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101.
Soil microbial properties and plant growth responses to carbon and water addition in a temperate steppe: the importance of nutrient availability 总被引:2,自引:0,他引:2
Background
Global climatic change is generally expected to stimulate net primary production, and consequently increase soil carbon (C) input. The enhanced C input together with potentially increased precipitation may affect soil microbial processes and plant growth.Methodology/Principal Findings
To examine the effects of C and water additions on soil microbial properties and plant growth, we conducted an experiment lasting two years in a temperate steppe of northeastern China. We found that soil C and water additions significantly affected microbial properties and stimulated plant growth. Carbon addition significantly increased soil microbial biomass and activity but had a limited effect on microbial community structure. Water addition significantly increased soil microbial activity in the first year but the response to water decreased in the second year. The water-induced changes of microbial activity could be ascribed to decreased soil nitrogen (N) availability and to the shift in soil microbial community structure. However, no water effect on soil microbial activity was visible under C addition during the two years, likely because C addition alleviated nutrient limitation of soil microbes. In addition, C and water additions interacted to affect plant functional group composition. Water addition significantly increased the ratio of grass to forb biomass in C addition plots but showed only minor effects under ambient C levels. Our results suggest that soil microbial activity and plant growth are limited by nutrient (C and N) and water availability, and highlight the importance of nutrient availability in modulating the responses of soil microbes and plants to potentially increased precipitation in the temperate steppe.Conclusions/Significance
Increased soil C input and precipitation would show significant effects on soil microbial properties and plant growth in the temperate steppe. These findings will improve our understanding of the responses of soil microbes and plants to the indirect and direct climate change effects. 相似文献102.
Zhang JJ Malekpour M Luo W Ge L Olaru F Wang XP Bah M Sado Y Heidet L Kleinau S Fogo AB Borza DB 《Journal of immunology (Baltimore, Md. : 1950)》2012,188(7):3268-3277
Membranous nephropathy (MN) is a leading cause of nephrotic syndrome in adults and a significant cause of end-stage renal disease, yet current therapies are nonspecific, toxic, and often ineffective. The development of novel targeted therapies requires a detailed understanding of the pathogenic mechanisms, but progress is hampered by the lack of a robust mouse model of disease. We report that DBA/1 mice as well as congenic FcγRIII(-/-) and FcRγ(-/-) mice immunized with a fragment of α3(IV) collagen developed massive albuminuria and nephrotic syndrome, because of subepithelial deposits of mouse IgG and C3 with corresponding basement membrane reaction and podocyte foot process effacement. The clinical presentation and histopathologic findings were characteristic of MN. Although immunized mice produced genuine anti-α3NC1 autoantibodies that bound to kidney and lung basement membranes, neither crescentic glomerulonephritis nor alveolitis ensued, likely because of the predominance of mouse IgG1 over IgG2a and IgG2b autoantibodies. The ablation of activating IgG Fc receptors did not ameliorate injury, implicating subepithelial deposition of immune complexes and consequent complement activation as a major effector pathway. We have thus established an active model of murine MN. This model, leveraged by the availability of genetically engineered mice and mouse-specific reagents, will be instrumental in studying the pathogenesis of MN and evaluating the efficacy of novel experimental therapies. 相似文献
103.
Yu S Zhang L Yan S Wang P Sanchez T Christ F Debyser Z Neamati N Zhao G 《Journal of enzyme inhibition and medicinal chemistry》2012,27(5):628-640
Four series of forty-five nitrogen-containing polyhydroxylated aromatics based on caffeic acid phenethyl ester were designed and synthesized as HIV-1 integrase (IN) inhibitors. Most of these compounds inhibited IN catalytic activities in low micromolar range. Among these new analogues, compounds 9e and 9f were the most potent IN inhibitors with IC(50) value of 0.7 μM against strand transfer reaction. Their key structure-activity relationships were also discussed. 相似文献
104.
Hui Yu Enwei Tian Linna Zheng Xiaoxia Deng Yufen Cheng Lianfu Chen Wei Wu Wattana Tanming Dayong Zhang Stephen G. Compton Finn Kjellberg 《Molecular ecology》2019,28(9):2391-2405
The ways that plant‐feeding insects have diversified are central to our understanding of terrestrial ecosystems. Obligate nursery pollination mutualisms provide highly relevant model systems of how plants and their insect associates have diversified and the over 800 species of fig trees (Ficus) allow comparative studies. Fig trees can have one or more pollinating fig wasp species (Agaonidae) that breed within their figs, but factors influencing their number remain to be established. In some widely distributed fig trees, the plants form populations isolated by large swathes of sea, and the different populations are pollinated by different wasp species. Other Ficus species with continuous distributions may present genetic signatures of isolation by distance, suggesting more limited pollinator dispersal, which may also facilitate pollinator speciation. We tested the hypothesis that Ficus hirta, a species for which preliminary data showed genetic isolation by distance, would support numerous pollinator species across its range. Our results show that across its range F. hirta displays clinal genetic variation and is pollinated by nine parapatric species of Valisia. This is the highest number of pollinators reported to date for any Ficus species, and it is the first demonstration of the occurrence of parapatric pollinator species on a fig host displaying continuous genetic structure. Future comparative studies across Ficus species should be able to establish the plant traits that have driven the evolution of pollinator dispersal behaviour, pollinator speciation and host plant spatial genetic structure. 相似文献
105.
106.
The hypoglycemic activity of fermented mushroom of Grifola frondosa rich in vanadium (GFRV) was studied in this paper. Alloxan- and adrenalin-induced hyperglycemic mice were used in the study.
The blood glucose and the HbA1c of the mice were analyzed respectively. After the mice were administered (ig) with GFRV, the
blood glucose and the HbA1c of alloxan-induced hyperglycemic mice decreased (p < 0.05, p < 0.01) and ascension of blood glucose induced by adrenalin was inhibited (p < 0.01). Also, the bodyweight of the alloxan-induced hyperglycemic mice was increased gradually. In the fermented mushroom
of G. frondosa, vanadium at lower doses in combination with G. frondosa induced significant decreases of the blood glucose and HbA1c levels in hyperglycemic mice. 相似文献
107.
Aims The two coexisting Leymus chinensis ecotypes exhibit remarkable divergences in adaptive strategies under drought and salinity in semi-humid meadows and semi-arid steppes. In order to detect the major genetic and environmental factors dominating the intraspecific phenotype variations and ecotype formation, the questions regarding the two distinct phenotypic forms (ecotypes) in L. chinensis were addressed: (i) did environments drive the L. chinensis ecotype formation? (ii) was there a molecular basis for the morphological divergence between the two ecotypes? (iii) which driving force dominated the intraspecies divergence, divergent natural selection, genetic drift or stabilizing selection?Methods We applied a series experiments on demographical, morphological and physiological traits of two Leymus chinensis ecotypes with gray green (GG) and yellow green (YG) leaf color in nine wild sites along a longitudinal gradient from 114° to 124°E in northeast China. The environmental data including mean annual precipitation, mean annual temperature, elevation and soil properties were collected. We compared the differences of morphological, physiological and genetic differentiations between the two ecotypes.Important findings The GG type exhibited stronger fitness than YG type from the population densities, morphological traits (e.g. shoot height, leaf area, leaf and seed weights et al.), leaf mass per area (LMA) and physiological traits [relative water content (RWC), proline, soluble sugar contents]. Most of above phenotypes (e.g. total shoot densities, spike length et al.) were significantly correlated with mean annual precipitation, mean annual temperature and soil water content (SWC), rarely a correlated with soil pH and soil nutrient. Transplanted populations showed convergence trend by their leaf chlorophyll contents and osmotic adjustments (proline and soluble sugar contents) in the greenhouse, but still exhibited their divergences between two ecotypes in the outdoor transplantation, suggesting that whether L. chinensis ecotype differentiated could be largely affected by the environmental conditions. Furthermore, by the comparison result of quantitative genetic variation (Q ST) values from phenotypes with theoretical neutral genetic differentiation (F ST), differentiation in phenotypic traits greatly surpassed neutral predictions, implying that directional natural selection played a crucial role in L. chinensis ecotype differentiation. In addition, microsatellite analysis from Neighbor-joining tree and Bayesian assignment generated into two groups according to ecotypes, indicating molecular genetic differentiation also propelled the two ecotypes divergence. We conclude that L. chinensis population variations were driven by combing divergent natural selection (precipitation, temperature and SWCs) along the large-scale gradient and significantly intrinsic genetic differentiation. 相似文献
108.
Linna Peng Sijin Cheng Yuan Lin Qionghua Cui Yingying Luo Jiahui Chu Mingming Shao Wenyi Fan Yamei Chen Ai Lin Yiyi Xi Yanxia Sun Lei Zhang Chao Zhang Wen Tan Ge Gao Chen Wu Dongxin Lin 《基因组蛋白质组与生物信息学报(英文版)》2018,16(4):262-268
Esophageal squamous-cell carcinoma (ESCC) is one of the most lethal malignancies in the world and occurs at particularly higher frequency in China. While several genome-wide association studies (GWAS) of germline variants and whole-genome or whole-exome sequencing studies of somatic mutations in ESCC have been published, there is no comprehensive database publically available for this cancer. Here, we developed the Chinese Cancer Genomic Database-Esophageal Squamous Cell Carcinoma (CCGD-ESCC) database, which contains the associations of 69,593 single nucleotide polymorphisms (SNPs) with ESCC risk in 2022 cases and 2039 controls, survival time of 1006 ESCC patients (survival GWAS) and gene expression (expression quantitative trait loci, eQTL) in 94 ESCC patients. Moreover, this database also provides the associations between 8833 somatic mutations and survival time in 675 ESCC patients. Our user-friendly database is a resource useful for biologists and oncologists not only in identifying the associations of genetic variants or somatic mutations with the development and progression of ESCC but also in studying the underlying mechanisms for tumorigenesis of the cancer. CCGD-ESCC is freely accessible at http://db.cbi.pku.edu.cn/ccgd/ESCCdb. 相似文献
109.
Jiani Tan Zhonghui Lai Ling Liu Wenyan Long Tong Chen Jun Zha Linna Wang Meiyu Chen Hui Ji Yisheng Lai 《The international journal of biochemistry & cell biology》2013,45(11):2632-2642
3-Oxo-29-noroleana-1,9(11),12-trien-2,20-dicarbonitrile (ONTD) is a novel synthetic derivative of glycyrrhetinic acid (GA), which has the ability to inhibit the proliferation of human hepatocellular carcinoma (HCC) cells. However, the mechanisms by which ONTD exerts its inhibitory effects remain elusive. The present study was conducted to investigate the cytotoxicity of ONTD in Bel-7402 cells and its molecular mechanisms. We found that ONTD depleted intracellular GSH, increased the level of ROS, and consequently induced mitochondrial permeability transition (MPT) leading to the release of apoptosis-inducing factor (AIF) and cytochrome c (Cyt c) to the cytosol. Mitochondrial alteration and subsequent apoptotic cell death in ONTD-treated Bel-7402 cells could be blocked by addition of exogenous antioxidants N-acetylcystein (NAC), GSH and the MTP inhibitor cyclosporin A (CsA). In addition, ONTD activated the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (MAPK) but not extracellular signal-regulated protein kinases (ERK 1/2). When the cells were exposed to SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor), the deregulation of the expression of apoptotic proteins was attenuated. Furthermore, 40 mg/kg ONTD significantly reduced tumor weight (?70.62%, p < 0.01) in the H22 tumor-bearing mouse model in vivo. Taken together, these findings provide the first experimental evidence supporting that ONTD could induce apoptosis of Bel-7402 cells via MAPK-mediated mitochondrial pathway and ONTD has the potential to be developed as a therapeutic agent for the treatment of HCC. 相似文献
110.