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Ecological stoichiometry is essential for understanding the biogeochemical cycle in forest ecosystems. However, previous studies of ecological stoichiometry have rarely considered the impacts of forest origins, which could help explain why to date so much uncertainty has been reported on this subject. In this study, we tried to reduce this uncertainty by examining carbon (C), nitrogen (N) and phosphorus (P) in roots, litter and soil in both natural and plantation forests throughout China. The sampled forest sites were divided into three groups according to the identified succession stages: early (ES), middle (MS) and late (LS) stages. Our results show that soil C, N and P concentrations were significantly higher in natural (NF) than in plantation (PL) forests. As succession/growth proceeded, P concentrations significantly increased in litter, roots and soil in NF, while the opposite occurred in PL. These results indicate that NF are able to use P more efficiently than PL, especially in the LS. Furthermore, the higher root N:P ratio indicates that the growth of PL was limited by P in both MS and LS. Our results also suggest that geographical and climatic factors are not the dominant factors in the differences in P between NF and PL, and, even more clearly and importantly, that native forests with native species are more capable of conserving P than planted forests, which are frequently less diverse and dominated by fast-growing non-site native species. These results will help improve biogeochemical models and forest management throughout the world. [ABSTRACT FROM AUTHOR]

Soil phosphorus (P) loss risk and environmental impact can be assessed by different soil test indicators such as soil P storage capacity (SPSC), a site-specific and reliable measurement of soil P status. In this study, the changing trends of soil P saturation ratio (PSR) and SPSC in red soil (equivalent to Ultisol) were discussed after 10 consecutive additions of P solution with 20 mg P L−1, and the relationships between Olsen-P, CaCl2-P, and PSR, SPSC also were evaluated. Results showed that the soil PSR was increased to 0.22 at the end of P addition, and the accumulated P was high to 1625 mg kg−1. The threshold PSR of the red soil was determined to be 0.10, and the SPSC significantly decreased from 242.0 mg kg−1 to −382.1 mg kg−1 with the increase of P addition times. When SPSC = 0, the accumulated P in red soil was 487.7 mg kg−1. Therefore, there existed four stages for the soil P management in red soil according to the changes of SPSC and Olsen-P: short supply stage of soil P (SPSC>88 mg kg−1 and Olsen-P ≤ 20 mg kg−1), stable supply stage of soil P (68 mg kg−1< SPSC≤88 mg kg−1 and 20 mg kg−1< Olsen-P ≤ 40 mg kg−1); over supply stage of soil P (0< SPSC≤68 mg kg−1 and 40 mg kg−1< Olsen-P ≤ 108 mg kg−1), and the high loss risk stage of soil P (SPSC≤0 and Olsen-P > 108 mg kg−1). In the last stage, P fertilization must be stopped and environmental protection measures must be taken immediately. [ABSTRACT FROM AUTHOR]

Paddy methane (CH 4 ) production is biologically dominated by methanogenic archaea that metabolize a variety of organic and/or inorganic carbon sources. Though formate is easily dissimilated into H 2 /CO 2 , formate-metabolizing methanogenic archaea are distinct from CO 2 -utilizing methanogen taxa. The identity of formate-metabolizing methanogenic archaea in paddy soil remains elusive. In this investigation, molecular approaches based on stable isotope probing (SIP) technique were conducted to identify the formate-metabolizing methanogenic archaea in paddy soil. CH 4 emission monitor, real-time quantitative PCR (qPCR) and Denaturing Gradient Gel Electrophoresis (DGGE) analyses consistently indicated that some methanogenic archaea metabolized 13 C-labeled formate in microcosm and accounted for a large portion of formate-metabolizing archaea in anoxic paddy soil. Phylogenetic identification further found that this guild was affiliated to Methanobacteriaceae . Taken together Methanobacteriaceae could be the dominant formate-metabolizing methanogenic archaea and play an important role in the CH 4 production in paddy soil. These findings would extend the extant knowledge on paddy methanogenic archaea and microbial-driven paddy CH 4 emission. [ABSTRACT FROM AUTHOR]

The interaction between cancer and its microenvironment is crucial for survival and development of cancerous cells. Tumor microenvironment is usually under hypoxia, which promotes tumor aggressiveness like growth, angiogenesis, and metastasis. How cancer cells respond to hypoxia and the resultant impact on tumorigenesis are not yet fully explored. Long noncoding RNAs (lncRNAs) have been attracting more and more attention since their functions in regulating gene expression at chromatic, transcriptional, and posttranscriptional levels were found. lncRNAs are dysregulated in cancer and act as oncogenes or tumor suppressors. Moreover, emerging evidence has been provided that the expression of lncRNAs changes with the stimulus of hypoxia and they in turn produce a significant influence on the hypoxia-inducible factor (HIF), the most common transcription regulator in response to hypoxia. In this review, we discuss the recent findings of hypoxia-responsive lncRNAs and summarize their interaction with hypoxia to further understand their roles in cancer growth, metabolism, angiogenesis, and metastasis and their potential for cancer diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Organic C has many benefits for soil, but it is depleted by tillage and crop harvest, and especially so for biofuel crops. Accordingly, strategies such as partially retaining stover or planting a cover crop can help ameliorate the negative effect of C removal. We used a long-term field experiment to study the impacts of stover retention and planting a cover crop on soil organic matter (SOM), its extractable components, and the soil microbial community. SOM chemical composition characterization was determined by electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) in sequential water, methanol (MeOH), and chloroform (CHCl 3) extracts. The characteristics of the soil bacterial community were measured by phospholipid fatty acid (PLFA), real-time quantitative PCR, and 16S rRNA gene sequence. The variations in total SOM content, total microbial biomass, and bacterial population were slight among treatments, but SOM chemical compounds, arbuscular mycorrhizal fungi (AMF) biomass, and bacterial structure changed significantly, and especially so in the coupled application of stover retention and cover crop. Specifically, stover retention enriched more lignin-like compounds in soil, whereas cover crop enriched more condensed hydrocarbons, and had more compounds with an aromaticity index (AI) > 0.5. The bacterial community was not altered by the cover crop, but the corn stover retention increased the relative abundances of Myxococcales (Deltaproteobacteria) and decreased that of Actinobacteria. Redundancy analysis (RDA) further revealed that the bacterial community in the stover treatments had a significant positive association with CHCl 3 -extracted chemical classes, i.e. unsaturated hydrocarbons and lipids, with the coupled application (stover and cover crop), and lignin and proteins with the corn stover only treatment. Taken together, our study shows how different C addition practices influence the molecular composition of SOM and the structure of soil microbial communities. • Soil carbon was characterized by ion cyclotron resonance mass spectrometry. • Corn stover and rye cover crop changed composition of extractable soil organic C. • Corn stover retention enhanced lignin-like compounds. • Cover crop enriched more condensed hydrocarbons. • Soil bacterial community composition corresponded to certain SOM compositions. [ABSTRACT FROM AUTHOR]

Fine particulate matter (PM2.5) is a typical air pollutant and has adverse health effects across the world, especially in the rapidly developing China due to significant air pollution. The PM2.5 pollution varies with time and space, and is dominated by the locations owing to the differences in geographical conditions including topography and meteorology, the land use and the characteristics of urbanization and industrialization, all of which control the pollution formation by influencing the various sources and transport of PM2.5. To characterize these parameters and mechanisms, the 5-year PM2.5 pollution patterns of Jiangsu province in eastern China with high-resolution was investigated. The Kriging interpolation method of geostatistical analysis (GIS) and the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model were conducted to study the spatial and temporal distribution of air pollution at 110 sites from national air quality monitoring network covering 13 cities. The PM2.5 pollution of the studied region was obvious, although the annual average concentration decreased from previous 72 to recent 50 μg m−3. Evident temporal variations showed high PM2.5 level in winter and low in summer. Spatially, PM2.5 level was higher in northern (inland, heavy industry) than that in eastern (costal, plain) regions. Industrial sources contributed highest to the air pollution. Backward trajectory clustering and potential source contribution factor (PSCF) analysis indicated that the typical monsoon climate played an important role in the aerosol transport. In summer, the air mass in Jiangsu was mainly affected by the updraft from near region, which accounted for about 60% of the total number of trajectories, while in winter, the long-distance transport from the northwest had a significant impact on air pollution. [ABSTRACT FROM AUTHOR]

Organic vegetable cultivation under plastic greenhouse conditions is expanding rapidly in the suburb of big cities in China due to the increasing demand for organic, out-of-season green vegetables and the sustainable development of agriculture. Phosphorus (P) is not only an important plant nutrient, but also a major contaminant in the water environment. However, information on the accumulation and distribution of P in organic vegetable soils under plastic greenhouse conditions is limited, relative to the open cultivation systems. Therefore, twenty-six plastic greenhouse vegetable soils (PGVS) were selected randomly from four representative organic vegetable cultivation sites located in the suburb of Nanjing, China. For comparison, 15 open vegetable soils (OVS) near the PGVS with similar soil and cultivation practices were selected. Soil pH, organic matter (OM) and the various P accumulation characteristics were investigated. We found that soil pH in PGVS were significantly decreased by 0.57–1.17 unit with obvious signs of acidification, compared with that in OVS. Soil OM was different for different sampling locations, but in general it was higher in PGVS than OVS. Soil total P (TP), inorganic P (P i ) and Olsen-P of PGVS were higher than those in the OVS. Olsen-P of all soil samples were far above the recommended optimum value of 20 mg kg −1 for field crops, and over 60% soil samples were considered excessive (>150 mg kg −1 ) in the PGVS and OVS. There were significant correlations between total P, available P and soil pH in those vegetable soils. Al-P/Fe-P ratio was also significantly correlated with vegetable soil pH (Y pH = 7.44–1.32 X Al-P/Fe-P , r = − 0.705, p < 0.01). Soil total P i was negatively correlated with soil pH in vegetable soils ( r = −0.328, p < 0.05), but the interactive effect of soil various P i and soil pH need to be further investigated through a series of controlled tests. Our results suggest that the rapid P accumulation and acidification make the current plastic greenhouse vegetable production in the study area unsustainable and better organic manure management practices need to be implemented to sustain crop yields while minimizing the impact of vegetable production on the environment. [ABSTRACT FROM AUTHOR]

The wide spread of nanoparticles (NPs) has caused tremendous concerns on agricultural ecosystem. Some metallic NPs, such as zinc oxide (ZnO), can be utilized as a nano-fertilizer when used at optimal doses. However, little is known about the responses of plant development and concomitant soil bacteria community to ZnO NPs. The present pot experiment studied the impacts of different doses of ZnO NPs and bulk ZnO (0, 1, 10, 100 mg ZnO/kg), on the growth of lettuce (Lactuca sativa L.) and the associated rhizospheric soil bacterial community. Results showed that at a dose of 10 mg/kg, ZnO NPs and bulk ZnO, enhanced the lettuce biomass and the net photosynthetic rate; whereas, the Zn content in plant tissue was higher in NPs treatment than in their bulk counterpart at 10 mg/kg dose or higher. For the underground observations, 10 mg/kg treatment doses (NPs or bulk) significantly changed the soil bacterial community structure, despite the non-significant variations in alpha diversity. Taxonomic distribution revealed that some lineages within Cyanobacteria and other phyla individually demonstrated similar or different responses to ZnO NPs and bulk ZnO. Moreover, some lineages associated with plant growth promotion were also influenced to different extents by ZnO NPs and bulk ZnO, suggesting the distinct microbial processes occurring in soil. Collectively, this study expanded our understanding of the influence of ZnO NPs on plant performance and the associated soil microorganisms.

The interaction between cancer and its microenvironment is crucial for survival and development of cancerous cells. Tumor microenvironment is usually under hypoxia, which promotes tumor aggressiveness like growth, angiogenesis, and metastasis. How cancer cells respond to hypoxia and the resultant impact on tumorigenesis are not yet fully explored. Long noncoding RNAs (lncRNAs) have been attracting more and more attention since their functions in regulating gene expression at chromatic, transcriptional, and posttranscriptional levels were found. lncRNAs are dysregulated in cancer and act as oncogenes or tumor suppressors. Moreover, emerging evidence has been provided that the expression of lncRNAs changes with the stimulus of hypoxia and they in turn produce a significant influence on the hypoxia-inducible factor (HIF), the most common transcription regulator in response to hypoxia. In this review, we discuss the recent findings of hypoxia-responsive lncRNAs and summarize their interaction with hypoxia to further understand their roles in cancer growth, metabolism, angiogenesis, and metastasis and their potential for cancer diagnosis and treatment.