Peanut yield and quality are seriously compromised by consecutive monoculturing in the red soil region of southern China. Soil fungi are, however, also critical to the ecological functioning of soils ...and plant health and were thus the study subject here. Using 454 pyrosequencing, the entire soil fungal communities of a field where peanut had been consecutively cultured for five years and another field, where peanut had been consecutively cultured for at least 20 years, and a control field with only a single peanut crop after a lay period were compared. Fungal richness, community composition, and relative taxon abundances in soil were compared among the fields and sampling times, the latter corresponding to the pod-bearing and the pod-maturing stages. Eight hundred fungal operational taxonomic units at 97% ITS sequence identity were found among 194,783 sequence reads derived from 18 separate soil samples. Members of the phylum Ascomycota strongly dominated the soil fungal communities and putative pathogens, such as Fusarium oxysporum, Leptosphaerulina australis, Phoma sp., and Bionectria ochroleuca showed higher relative abundances in the fields where peanut was consecutively monocultured, compared to the control field, at the expense of putatively plant-beneficial fungal groups, such as Trichoderma sp., a glomeromycotan fungus, and Mortierella elongata. The results suggest that the accumulations of fungal pathogen loads at the expense of plant-beneficial fungi in the soil appear likely explanations for yield declines as a consequence of consecutive peanut cultivation.
•Shifts in soil fungal community composition and structure were assessed by 454 pyrosequencing.•Consecutive peanut monoculturing increased putative fungal pathogens.•Consecutive peanut monoculturing decreased putative beneficial soil fungi.•An ecological imbalance of soil fungi appears to explain yield declines over continuous cropping.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Grain refinement can strengthen the mechanical properties of materials according to the classical Hall-Petch relationship but does not always result in better corrosion resistance. During the past ...few decades, various techniques have been dedicated to refining grain, along with relevant studies on corrosion behavior, including general corrosion, pitting corrosion, and stress corrosion cracking. However, the fundamental consensus on how grain size influences corrosion behavior has not been reached. This paper reviews existing literature on the beneficial and detrimental effects of grain refinement on corrosion behavior. Moreover, the effects of microstructural changes (i.e., grain boundary, dislocation, texture, residual stress, impurities, and second phase) resulting from grain refinement on corrosion behavior are discussed. The grain refinement not only has an impact on the corrosion performance, but also results in microstructural changes that have a non-negligible effect on corrosion behavior or even outweigh that of grain refinement. Grain size is not the only factor affecting the corrosion behavior of metallic materials; thus, the overall influence of microstructures on corrosion behavior should be understood.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The access of rhizobia to legume host is a prerequisite for nodulation. Rhizobia are poorly motile in soil, while filamentous fungi are known to grow extensively across soil pores. Since root ...exudates-driven bacterial chemotaxis cannot explain rhizobial long-distance dispersal, mycelia could constitute ideal dispersal networks to help rhizobial enrichment in the legume rhizosphere from bulk soil. Thus, we hypothesized that mycelia networks act as vectors that enable contact between rhizobia and legume and influence subsequent nodulation. By developing a soil microcosm system, we found that a facultatively biotrophic fungus, Phomopsis liquidambaris, helps rhizobial migration from bulk soil to the peanut (Arachis hypogaea) rhizosphere and, hence, triggers peanut-rhizobium nodulation but not seen in the absence of mycelia. Assays of dispersal modes suggested that cell proliferation and motility mediated rhizobial dispersal along mycelia, and fungal exudates might contribute to this process. Furthermore, transcriptomic analysis indicated that genes associated with the cell division, chemosensory system, flagellum biosynthesis, and motility were regulated by Ph. liquidambaris, thus accounting for the detected rhizobial dispersal along hyphae. Our results indicate that rhizobia use mycelia as dispersal networks that migrate to legume rhizosphere and trigger nodulation. This work highlights the importance of mycelial network-based bacterial dispersal in legume-rhizobium symbiosis.
Full text
Available for:
NUK, SBMB, SBNM, UL, UM, UPUK
The quantity and quality of peanut yields are seriously compromised by consecutive monoculture in the subtropical regions of China. Root exudates, which represent a growth regulator in peanut–soil ...feedback processes, play a principal role in soil sickness. The growth inhibition of a species in an in vitro bioassay enriched with root exudates and allelochemicals is commonly viewed as evidence of an allelopathic interaction. However, for some of these putative examples of allelopathy, the results have not been verified in more natural settings with plants continuously growing in soil. In this study, the phenolic acids in peanut root exudates, their retention characteristics in an Udic Ferrosol, and their effects on rhizosphere soil microbial communities and peanut seedling growth were studied. Phenolic acids from peanut root exudates were quickly metabolized by soil microorganisms and did not accumulate to high levels. The peanut root exudates selectively inhibited or stimulated certain communal bacterial and fungal species, with decreases in the relative abundance of the bacterial taxa Gelria glutamica, Mitsuaria chitosanitabida, and Burkholderia soli and the fungal taxa Mortierella sp. and Geminibasidium hirsutum and increases in the relative abundance of the bacterial taxon Desulfotomaculum ruminis and the fungal taxa Fusarium oxysporum, Bionectria ochroleuca and Phoma macrostoma. The experimental application of phenolic acids to non-sterile and sterile soil revealed that the poor performance of the peanut plants was attributed to changes in the soil microbial communities promoted by phenolic acids. These results suggest that pathogenic fungal accumulation at the expense of such beneficial microorganisms as plant growth promoting rhizobacteria, mycorrhizal fungi induced by root exudates, rather than direct autotoxicity induced by root exudates, might represent the principal cause underlying the soil sickness associated with peanut plants. We hope that our study will motivate researchers to integrate the role of soil microbial communities in allelopathic research, such that their observed significance in soil sickness during continuous monocropping of fields can be further explored.
•Phenolic acids were mostly metabolized by microbes rather than accumulation in soil.•Peanut root exudates increased pathogenic fungi and decreased beneficial microbes.•Pseudomonads community responded sensitively to peanut root exudates.•Bad peanut performance was due to changes of soil microbes incited by phenolic acids.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► Double ridge-furrow mulching (DRM) in corn affected soil properties. ► DRM increased microbial biomass C two times over the non-mulching control (CK). ► There was a significant negative correlation ...between SOC and mineral N. ► DRM increased soil light fraction C, with the potential of enhancing sustainability.
Understanding plant–soil relationships may help maximize crop productivity while maintaining and improving soil quality. Field experiments were conducted in 2006 and 2007 at the Dryland Agricultural Experimental Station of the Loess Plateau, Lanzhou University, China, to determine the effects of various ridge-furrow and plastic-mulching techniques on the growth and yield of maize (
Zea mays L.) and soil biochemical properties.
Five treatments were designed: (1) flat-plot sowing without ridge-furrow mulching (CK), (2) large (80
cm) and small (40
cm) ridges alternated and fully mulched with plastic (DRM), (3) on-furrow sowing with plastic mulch applied only on the ridge at a row spacing of 60
cm and 40
cm alternatively (RM), (4) flat-plot sowing with plastic mulch at a row spacing of 60
cm and 40
cm alternatively (NM), and (5) flat-plot sowing with plastic mulch at a row spacing of 80
cm and 40
cm alternatively (WM).
The results showed that film mulching enhanced soil microbial biomass; where microbial biomass carbon (MBC) in the DRM treatment reached 633
mg
kg
−1 at harvest in 2007, three times the MBC of the CK. The MBC:SOC ratios were 8.8%, 7.1%, 5.7% and 5.4% in DRM, RM, NM and WM, respectively. The ridge-furrow with plastic-mulching increased soil light fraction carbon (LFOC) in both years, averaging up to 1.04
g
kg
−1 at harvest. Underground plant biomass increased substantially in the mulching treatments, especially in DRM. Positive correlations were found between total biomass and LFOC, between MBC and LFOC, and between MBC and available phosphorus (AP), but a negative correlation between SOC and soil mineral nitrogen (MN). The carbon to phosphorus (C/P) ratio was highest in DRM among treatments, but the content of SOC, MN, and C/N ratio in DRM was lowest, suggesting that the DRM treatment strengthened the interactions between maize and soil, and that the increased content of LFOC with time provides a basis for increasing productivity in future years.
In conclusion, the ridge-furrow and plastic-mulching technique brought about a challenge in maintaining soil fertility, but this technology provides a potential opportunity of substantially increasing crop yields in semiarid rainfed regions.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The satellite-observed nighttime light emission (NTLE) data provide a new method for scrutinizing the footprint of human settlements. Changing NTLEs can be attributed to the direct/indirect ...influences of highly complex factors that are beyond the ability of simple statistical models to distinguish. Besides, the relatively coarse resolution of the NTLE products combined with light from human settlements may produce misleading results, as the relationship between spatiotemporal heterogeneity in the growth of developed land (e.g., urban and rural residences, shopping centers, industrial parks, mining plants, and transportation facilities) and the associated NTLEs has not been adequately analyzed. In this study, we developed a total nighttime brightness index (TotalNTBI) to measure the NTLEs with the defense meteorological satellite program/operational linescan system (DMSP/OLS) nighttime light data enhanced by sharpening the edges of the pixels. Thirty-six key cities in China were selected to investigate the relationship between the total developed land area and the associated TotalNTBI from 2000 to 2013 using panel regression and a simplified structural equation model (SEM). The results show that the overall trend in TotalNTBI agreed well with that of the total developed land area (mean adjusted R2 = 0.799). The panel regression models explained approximately 71.8% of the variance of total developed land area and 92.4% of the variance in TotalNTBI. The SEM revealed both the direct and indirect influences of independent variables on the total developed land area and the associated TotalNTBI. This study may provide useful information for decision-makers and researchers engaged in sustainable land development, urban management, and regional developmental inequality, focusing on recent issues, such as retrospective analysis of human footprint with sharpened nighttime NTLE products, the loss of natural and semi-natural land due to the sprawling developed land area indicated by intensively lit area, and the low efficiency of land development indicated by the anomalies of developed land area and associated NTBIs.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
Quantum key distribution (QKD) enables secure key exchanges between two remote users. The ultimate goal of secure communication is to establish a global quantum network. The existing field ...tests suggest that quantum networks are feasible. To achieve a practical quantum network, we need to overcome several challenges including realizing versatile topologies for large scales, simple network maintenance, extendable configuration and robustness to node failures. To this end, we present a field operation of a quantum metropolitan-area network with 46 nodes and show that all these challenges can be overcome with cutting-edge quantum technologies. In particular, we realize different topological structures and continuously run the network for 31 months, by employing standard equipment for network maintenance with an extendable configuration. We realize QKD pairing and key management with a sophisticated key control centre. In this implementation, the final keys have been used for secure communication such as real-time voice telephone, text messaging and file transmission with one-time pad encryption, which can support 11 pairs of users to make audio calls simultaneously. Combined with intercity quantum backbone and ground–satellite links, our metropolitan implementation paves the way toward a global quantum network.
Background and Purpose
Vascular inflammation, including the expression of inflammatory cytokines in endothelial cells, plays a critical role in hyperhomocysteinaemia‐associated vascular diseases. ...Cathepsin V, specifically expressed in humans, is involved in vascular diseases through its elastolytic and collagenolytic activities. The aim of this study was to determine the effects of cathepsin V on l‐homocysteine‐induced vascular inflammation.
Experimental Approach
A high methionine diet‐induced hyperhomocysteinaemic mouse model was used to assess cathepsin V expression and vascular inflammation. Cultures of HUVECs were challenged with l‐homocysteine and the cathepsin L/V inhibitor SID to assess the pro‐inflammatory effects of cathepsin V. Transfection and antisense techniques were utilized to investigate the effects of cathepsin V on the dual‐specificity protein phosphatases (DUSPs) and MAPK pathways.
Key Results
Cathepsin L (human cathepsin V homologous) was increased in the thoracic aorta endothelial cells of hyperhomocysteinaemic mice; l‐homocysteine promoted cathepsin V expression in HUVECs. SID suppressed the activity of cathepsin V and reversed the up‐regulation of inflammatory cytokines (IL‐6, IL‐8 and TNF‐α), adhesion and chemotaxis of leukocytes and vascular inflammation induced by l‐homocysteine in vivo and in vitro. Increased cathepsin V promoted the degradation of DUSP6 and DUSP7, phosphorylation and subsequent nuclear translocation of ERK1/2, phosphorylation of STAT1 and expression of IL‐6, IL‐8 and TNF‐α.
Conclusions and Implications
This study has identified a novel mechanism, which shows that l‐homocysteine‐induced upregulation of cathepsin V mediates vascular endothelial inflammation under high homocysteine condition partly via ERK1/2/STAT1 pathway. This mechanism could represent a potential therapeutic target in hyperaemia‐associated vascular diseases.
Linked Articles
This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc
Full text
Available for:
BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
The high strength martensite steels are widely used in aerospace, ocean engineering, etc., due to their high strength, good ductility and acceptable corrosion resistance. This paper provides a review ...for the influence of microstructure on corrosion behavior of high strength martensite steels. Pitting is the most common corrosion type of high strength stainless steels, which always occurs at weak area of passive film such as inclusions, carbide/intermetallic interfaces. Meanwhile, the chromium carbide precipitations in the martensitic lath/prior austenite boundaries always result in intergranular corrosion. The precipitation, dislocation and grain/lath boundary are also used as crack nucleation and hydrogen traps, leading to hydrogen embrittlement and stress corrosion cracking for high strength martensite steels. Yet, the retained/reversed austenite has beneficial effects on the corrosion resistance and could reduce the sensitivity of stress corrosion cracking for high strength martensite steels. Finally, the corrosion mechanisms of additive manufacturing high strength steels and the ideas for designing new high strength martensite steel are explored.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
