32 research outputs found
Distinct biogeographic patterns for archaea, bacteria, and fungi along the vegetation gradient at the continental scale in Eastern China
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in mSystems 2 (2017): e00174-16, doi:10.1128/mSystems.00174-16.The natural forest ecosystem in Eastern China, from tropical forest to boreal forest, has declined due to cropland development during the last 300 years, yet little is known about the historical biogeographic patterns and driving processes for the major domains of microorganisms along this continental-scale natural vegetation gradient. We predicted the biogeographic patterns of soil archaeal, bacterial, and fungal communities across 110 natural forest sites along a transect across four vegetation zones in Eastern China. The distance decay relationships demonstrated the distinct biogeographic patterns of archaeal, bacterial, and fungal communities. While historical processes mainly influenced bacterial community variations, spatially autocorrelated environmental variables mainly influenced the fungal community. Archaea did not display a distance decay pattern along the vegetation gradient. Bacterial community diversity and structure were correlated with the ratio of acid oxalate-soluble Fe to free Fe oxides (Feo/Fed ratio). Fungal community diversity and structure were influenced by dissolved organic carbon (DOC) and free aluminum (Ald), respectively. The role of these environmental variables was confirmed by the correlations between dominant operational taxonomic units (OTUs) and edaphic variables. However, most of the dominant OTUs were not correlated with the major driving variables for the entire communities. These results demonstrate that soil archaea, bacteria, and fungi have different biogeographic patterns and driving processes along this continental-scale natural vegetation gradient, implying different community assembly mechanisms and ecological functions for archaea, bacteria, and fungi in soil ecosystems.This research was financially supported by the National Natural Science Foundation of China (grant number 41520104001), the 111 Project, and the Fundamental Research Funds for the Central Universities
Effects of water stress on starch synthesis and accumulation of two rice cultivars at different growth stages
Rice is a water intensive crop and soil water conditions affect rice yield and quality. However, there is limited research on the starch synthesis and accumulation of rice under different soil water conditions at different growth stages. Thus, a pot experiment was conducted to explore the effects of IR72 (indica) and Nanjing (NJ) 9108 (japonica) rice cultivars under flood-irrigated treatment (CK, 0 kPa), light water stress treatment (L, -20 ± 5 kPa), moderate water stress treatment (M, -40 ± 5 kPa) and severe water stress treatment (S, -60 ± 5 kPa) on the starch synthesis and accumulation and rice yield at booting stage (T1), flowering stage (T2) and filling stage (T3), respectively. Under LT treatment, the total soluble sugar and sucrose contents of both cultivars decreased while the amylose and total starch contents increased. Starch synthesis-related enzyme activities and their peak activities at mid-late growth stage increased as well. However, applying MT and ST treatments produced the opposite effects. The 1000-grain weight of both cultivars increased under LT treatment while the seed setting rate increased only under LT3 treatment. Compared with CK, water stress at booting stage decreased grain yield. The principal component analysis (PCA) showed that LT3 got the highest comprehensive score while ST1 got lowest for both cultivars. Furthermore, the comprehensive score of both cultivars under the same water stress treatment followed the trend of T3 > T2 > T1, and NJ 9108 had a better drought-resistant ability than IR72. Compared with CK, the grain yield under LT3 increased by 11.59% for IR72 and 16.01% for NJ 9108, respectively. Overall, these results suggested that light water stress at filling stage could be an effective method to enhance starch synthesis-related enzyme activities, promote starch synthesis and accumulation and increase grain yield
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Reduction in the exposure risk of farmer from e-waste recycling site following environmental policy adjustment: a regional scale view of PAHs in paddy fields
Farmland contamination by polycyclic aromatic hydrocarbons (PAHs) has drawn increasing attention across China with enhanced regulations and environmental policies proposed by government to protect soil environment safety. As the informal electronic waste (e-waste) dismantling activities were forbidden under recent environmental regulation, this study compared levels, compositions, spatial distributions, human health risks of PAHs in paddy soil within the vicinity of an e-waste recycling area in southeastern China, with 129 and 150 soil samples collected in 2011 and 2016, respectively. The soil contamination was dominated with high molecular weight PAHs. The mean concentration of EPA 16 PAHs decreased from 590.4 ± 337.2 μg kg in 2011 to 407.3 ± 232.2 μg kg in 2016. Distribution maps of soil PAHs concentration displayed the temporal change in spatial. Principal component analysis together with diagnostic ratios revealed the combustion of biomass and coal in industrial and unregulated e-waste dismantling were the main sources of PAHs in the study area. Both deterministic and probabilistic assessments demonstrated reduced exposure risk for farmers from 2011 to 2016. Sensitivity analysis revealed that exposure frequency (EF) is the most influential parameter for the total variance in the risk assessment model. This study implied that the more stringent environmental policy and regulation can lead reductions in soil contamination with PAHs. [Abstract copyright: Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.
Ultrasonic-Assisted Extraction of Antioxidants from <i>Perilla frutescens</i> Leaves Based on Tailor-Made Deep Eutectic Solvents: Optimization and Antioxidant Activity
The development of natural antioxidants to replace synthetic compounds is attractive. Perilla frutescens leaves were proven to be rich in antioxidants. The extraction of antioxidants from Perilla leaves via ultrasonic-assisted extraction (UAE) based on choline chloride-based deep eutectic solvents (DESs) was studied. Firstly, several DESs were prepared, and their extraction effects were compared. Secondly, the extraction process was optimized by single-factor experiments and response surface methodology (RSM). Finally, the optimization results were verified and compared with the results of traditional solvent-based UAE. The effects of solvents on the surface cell morphology of Perilla frutescens leaves were characterized by scanning electron microscopy (SEM). Choline chloride-acetic acid-based DES (ChCl-AcA) extract showed a relatively high ferric-reducing antioxidant activity (FRAP) and 2,2-diphenyl-1-picrylhyldrazyl radical scavenging rate (DPPH). Under the optimal operating conditions (temperature 41 °C, liquid–solid ratio 33:1, ultrasonic time 30 min, water content 25%, ultrasonic power 219 W), the experimental results are as follows: DPPH64.40% and FRAP0.40 mM Fe(II)SE/g DW. The experimental and predicted results were highly consistent with a low error (Perilla frutescens leaves. The cytotoxicity and biodegradability of the extract will be further verified in a future work
J. Phys. Chem. Ref. Data
A comprehensive database on physical properties of ionic liquids (ILs), which was collected from 109 kinds of literature sources in the period from 1984 through 2004, has been presented. There are 1680 pieces of data on the physical properties for 588 available ILs, from which 276 kinds of cations and 55 kinds of anions were extracted. In terms of the collected database, the structure-property relationship was evaluated. The correlation of melting points of two most common systems, disubstituted imidazolium tetrafluoroborate and disubstituted imidazolium hexafluorophosphate, was carried out using a quantitative structure-property relationship method. (c) 2006 American Institute of Physics.A comprehensive database on physical properties of ionic liquids (ILs), which was collected from 109 kinds of literature sources in the period from 1984 through 2004, has been presented. There are 1680 pieces of data on the physical properties for 588 available ILs, from which 276 kinds of cations and 55 kinds of anions were extracted. In terms of the collected database, the structure-property relationship was evaluated. The correlation of melting points of two most common systems, disubstituted imidazolium tetrafluoroborate and disubstituted imidazolium hexafluorophosphate, was carried out using a quantitative structure-property relationship method. (c) 2006 American Institute of Physics
Fluid Phase Equilib.
Melting points are significant properties for the design and application of ionic liquids (ILs) as green solvents. In this work, the melting points of two kinds of room temperature ionic liquids, imidazolium tetrafluoroborates and imidazolium hexafluorophosphates, were investigated by using a quantitative structure-property relationship (QSPR) approach. The employed descriptors were firstly selected by studying the optimized geometries of four ILs: EmimBF(4), BmimBF(4), EmimPF(6) and BmimPF(6). Electrostatic, quantum mechanical and topological descriptors were considered efficient to describe melting points of ionic liquids. A three-parameter model with the squared correlation coefficient, R-2, of 0.9047 is developed for 16 kinds of imidazolium tetrafluoroborates, and a six-parameter equation with R-2 of 0.9207 is obtained for 25 kinds of imidazolium hexafluorophosphates. The proposed models can be useful for the prediction of the melting points of ILs with similar structural features. (c) 2006 Elsevier B.V. All rights reserved.Melting points are significant properties for the design and application of ionic liquids (ILs) as green solvents. In this work, the melting points of two kinds of room temperature ionic liquids, imidazolium tetrafluoroborates and imidazolium hexafluorophosphates, were investigated by using a quantitative structure-property relationship (QSPR) approach. The employed descriptors were firstly selected by studying the optimized geometries of four ILs: EmimBF(4), BmimBF(4), EmimPF(6) and BmimPF(6). Electrostatic, quantum mechanical and topological descriptors were considered efficient to describe melting points of ionic liquids. A three-parameter model with the squared correlation coefficient, R-2, of 0.9047 is developed for 16 kinds of imidazolium tetrafluoroborates, and a six-parameter equation with R-2 of 0.9207 is obtained for 25 kinds of imidazolium hexafluorophosphates. The proposed models can be useful for the prediction of the melting points of ILs with similar structural features. (c) 2006 Elsevier B.V. All rights reserved
1-Allyl-3-methylimidazolium halometallate ionic liquids as efficient catalysts for the glycolysis of poly(ethylene terephthalate)
Series of 1-allyl-3-methylimidazolium halometallate ionic liquids (ILs) were synthesized and used to degrade poly(ethylene terephthalate) (PET) as catalysts in the solvent of ethylene glycol. One important feature of these new IL catalysts is that most of them, especially [amim][CoCl3] and [amim][ZnCl3], exhibit higher catalytic activity under mild reaction condition, compared to the traditional catalysts [e.g., Zn(Ac)2], the conventional IL catalysts (e.g., [bmim]Cl), Fe-containing magnetic IL catalysts (e.g., [bmim][FeCl4]), and metallic acetate IL catalysts (e.g., [Deim][Zn(OAc)3]). For example, using [amim][ZnCl3] as catalyst, the conversion of PET and the selectivity of bis(hydroxyethyl) terephthalate (BHET) reach up to 100% and 80.1%, respectively, under atmospheric pressure at 175 degrees C for only 1.25 h. Another important feature is that BHET can be easily separated from the catalyst and has a high purity. Finally, based on the experimental phenomena, in -situ infrared spectra, and experimental results, the possible mechanism of degradation with synthesized IL is proposed. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 201
Hepatocellular carcinoma: signaling pathways, targeted therapy, and immunotherapy
Abstract Hepatocellular carcinoma (HCC) is the most common primary liver cancer with a high mortality rate. It is regarded as a significant public health issue because of its complicated pathophysiology, high metastasis, and recurrence rates. There are no obvious symptoms in the early stage of HCC, which often leads to delays in diagnosis. Traditional treatment methods such as surgical resection, radiotherapy, chemotherapy, and interventional therapies have limited therapeutic effects for HCC patients with recurrence or metastasis. With the development of molecular biology and immunology, molecular signaling pathways and immune checkpoint were identified as the main mechanism of HCC progression. Targeting these molecules has become a new direction for the treatment of HCC. At present, the combination of targeted drugs and immune checkpoint inhibitors is the first choice for advanced HCC patients. In this review, we mainly focus on the cutting‐edge research of signaling pathways and corresponding targeted therapy and immunotherapy in HCC. It is of great significance to comprehensively understand the pathogenesis of HCC, search for potential therapeutic targets, and optimize the treatment strategies of HCC