作者机构：
[Xue, Shengguo; Wu, Chuan; Mo, Jingyu; Zou, Qi] Cent S Univ, Sch Met & Environm, Changsha 410083, Hunan, Peoples R China.;[Pan, Weisong] Hunan Agr Univ, Coll Biosci & Biotechnol, Changsha 410128, Hunan, Peoples R China.;[Lou, Laiqing] Nanjing Agr Univ, Coll Life Sci, Nanjing 210095, Jiangsu, Peoples R China.;[Wong, Ming Hung] Hong Kong Inst Educ, CHEER, Tai Po, Hong Kong, Peoples R China.
通讯机构：
[Xue, Shengguo] C;Cent S Univ, Sch Met & Environm, Changsha 410083, Hunan, Peoples R China.
关键词：
Arsenic;Radial oxygen loss (ROL);Rice;Silicon fertilization
摘要：
Arsenic (As) contamination of paddy soils has adversely affected the health of millions of people those consuming rice for staple food. The present study was aimed at investigating the effects of silicon (Si) fertilization on As uptake, speciation in rice plants with different radial oxygen loss (ROL). Six genotypes were planted in pot soils under greenhouse conditions until late tillering state. The results showed that the rates of ROL were higher in hybrid rice genotypes varying from 19.76 to 27 mu mol O-2 g(-1) root dry weight h(-1) than that in conventional indica rice genotypes varying from 9.55 to 15.41 mu mol O-2 g(-1) root dry weight h(-1). Si addition significantly increased straw biomass (p < 0.005), but with no significant effects on root biomass. Si fertilization significantly reduced shoot and root total As concentrations (p < 0.001) in six genotypes grown in 40 mg As/kg soil. Si addition decreased the inorganic As in shoots of 'Xiangfengyou-9' with lower ROL and 'Xiangwanxian-12' with higher ROL by 31% and 25% respectively and had the tendency to increase DMA concentrations. It is potential to reduce As contamination of rice efficiently by combining Si fertilization and selecting genotypes with high radial oxygen loss. (C) 2015 Elsevier Ltd. All rights reserved.
通讯机构：
[Liang, Yizeng] C;Cent South Univ, Coll Chem & Chem Engn, Changsha 410083, Hunan, Peoples R China.
摘要：
Based on the theory that a large partial least squares (PLS) regression coefficient on autoscaled data indicates an important variable, a novel strategy for variable selection called iteratively variable subset optimization (IVSO) is proposed in this study. In addition, we take into consideration that the optimal number of latent variables generated by cross-validation will make a great difference to the regression coefficients and sometimes the difference can even vary by several orders of magnitude. In this work, the regression coefficients generated in every sub-model are normalized to remove the influence. In each iterative round, the regression coefficients of each variable obtained from the sub-models are summed to evaluate their importance level. A two-step procedure including weighted binary matrix sampling (WBMS) and sequential addition is employed to eliminate uninformative variables gradually and gently in a competitive way and reduce the risk of losing important variables. Thus, IVSO can achieve high stability. Investigated by using one simulated dataset and two NIR datasets, IVSO shows much better prediction ability than two other outstanding and commonly used methods, Monte Carlo uninformative variable elimination (MC-UVE) and competitive adaptive reweighted sampling (CARS). The MATLAB code for implementing IVSO is available in the ESI.
摘要：
Developing the biomass energy industry has become a new idea for solving the energy crisis. The plant, Miscanthus, which has a high content of cellulose, is an optimal material for biorefinery. In this review, the characteristics of Miscanthus are first briefly introduced. Then, the biorefinery general scheme, main process, and existing problems of Miscanthus are summarized. Finally, its application is prospected.
摘要：
The competitive immunoreaction technique for the detection of 2,4-dichlorophenoxyacetic acid(2,-4D) was described in this paper based on quartz crystal microbalance (QCM) with gold nanoparticles enhanced surfaces. The results showed the response of the sensor has a good linear relationship with 2,4-D concentrations in the range of 13.3-666.7 ng/mL with a detection limit at about 13.0 ng/mL. This work also provides a promising alternative approach for immuno-detection of other small molecules. The sensor could be regenerated under mild conditions simply by immersing the sensor into glycine buffer solution to break the antibody-antigen linkage. It was found that the proposed sensor could be reused at least nine runs without obvious loss of sensitivity. (C) 2013 Elsevier B.V. All rights reserved.
作者机构：
[唐巧; 刘素纯] College of Food Science and Technology Hunan Agricultural University, Changsha 410128, China;[刘素纯] Key Laboratories of Food Science and Biotechnology of Hunan Province, Changsha 410128, China;[胡茂丰] College of Bioscience and Biotechnology Hunan Agricultural University, Changsha 410128, China
通讯机构：
College of Food Science and Technology Hunan Agricultural University, China
关键词：
cytochrome c;humic acid;in vivo;in vitro;extracellular electron transfer
摘要：
Out-membrane cytochrome c (Cyt c) plays an important role carrying electrons from the inside of microbes to outside electron acceptors. However, the active sites of Cyt c are wrapped by nonconductive peptide chains, hindering direct extracellular electron transfer (EET). Humic acids (HA) have been previously proven to efficiently facilitate EET. However, the inherent mechanism of HA-stimulated EET has not been well interpreted. Here, to probe the mechanism behind HA-stimulated EET, we studied the interaction between Cyt c and HA. The attachment of active in vivo Cyt c on a graphite electrode was achieved when MR-1 cells were self-assembled on the electrode surface. Pure horse-heart Cyt c was covalently immobilized on an electrode via 4-aminobenzoic acid to create an active in vitro Cyt c-enriched surface. Cyclic voltammetric measurements and scanning electron microscopy confirmed the immobilization of bacterial cells and pure Cyt c protein. Electrochemical methods revealed that HA could enhance the electrocatalytic current of both in vitro and in vivo Cyt c towards oxygen and thiosulfate, suggesting enhanced EET. The blue-shifted soret band in the UV-Vis spectra and changes in the excitation/emission matrix fluorescence spectra demonstrated that Cyt c interacted with HA to form organic complexes via electrostatic or hydrogen-bonding interactions. The results will help understand electron shuttle-stimulated EET and develop bacteriabased bioremediation and bioenergy technologies.
摘要：
A pot experiment was conducted to investigate the effects of root oxidation on arsenic (As) dynamics in the rhizosphere and As sequestration on rice roots. There were significant differences (P < 0.05) in pH values between rhizosphere and non-rhizosphere soils, with pH 5.68–6.16 in the rhizosphere and 6.30–6.37 in non-rhizosphere soils as well as differences in redox potentials (P < 0.05). Percentage arsenite was lower (4%–16%) in rhizosphere soil solutions from rice genotypes with higher radial oxygen loss (ROL) compared with genotypes with lower ROL (P < 0.05). Arsenic concentrations in iron plaque and rice straw were significantly negatively correlated (R = ?0.60, P < 0.05). Genotypes with higher ROL (TD71 and Yinjingruanzhan) had significantly (P < 0.001) lower total As in rice grains (1.35 and 0.96 mg/kg, respectively) compared with genotypes with lower ROL (IAPAR9, 1.68 mg/kg; Nanyangzhan 2.24 mg/kg) in the As treatment, as well as lower inorganic As (P < 0.05). The present study showed that genotypes with higher ROL could oxidize more arsenite in rhizosphere soils, and induce more Fe plaque formation, which subsequently sequestered more As. This reduced As uptake in aboveground plant tissues and also reduced inorganic As accumulation in rice grains. The study has contributed to further understanding the mechanisms whereby ROL influences As uptake and accumulation in rice.
摘要：
The study on the second generation bio-fuel is a hot area of current research of renewable energy. Among series of key points in this area, the role of β-glucosidase in the degradation of intermediate gluco-oligosaccharides limits the rate of the complete saccharification of lignocellulose. In this study, a new β-glucosidase gene, unglu135B12, which was isolated from a metagenomic library of rumen of cattle feeding with Miscanthus sinensis by the function-based screening, encodes a 779 amino acid polypeptide that contains a catalytic domain belonging to glycoside hydrolase family 3 (GH3). It was recombinantly expressed, purified and biochemically characterized. The recombinant β-glucosidase, unglu135B12, displayed optimum enzymatic activity at pH 5.0 at 38°C, and showed the highest specific activity of 2.5 × 103 U/mg under this optimal condition to p-nitrophenyl-β-D-glucopyranoside (pNPG), and its Km and Vmax values were 0.309 mmol/L and 7.292 μmol/min, respectively. In addition, the presence of Ca2+, K+, Na+ slightly improved β-glucosidase activity of unglu135B12 by about 5%, while about 10 ~ 85% loss of β-glucosidase activity was induced by addition of Mn2+, Fe3+, Zn2+, Cu2+. Interestingly, unglu135B12 was activated by glucose at the concentration lower than 40 mM. Our findings indicate that unglu135B12 is a new β-glucosidase derived from rumen of cattle, and it might be a potent candidate for saccharification of lignocellulose in industrial application.
摘要：
The microbial community structures in an integrated two-phase anaerobic reactor (ITPAR)were investigated by 16S rDNA clone library technology. The 75 L reactor was designed with a 25 L rotating acidogenic unit at the top and a 50 L conventional upflow methanogenic unit at the bottom, with a recirculation connected to the two units. The reactor had been operated for 21 stages to co-digest fruit/vegetable wastes and wheat straw, which showed a very good biogas production and decomposition of cellulosic materials. The results showed that many kinds of cellulose and glycan decomposition bacteria related with Bacteroidales,Clostridiales and Syntrophobacterales were dominated in the reactor, with more bacteria community diversities in the acidogenic unit. The methanogens were mostly related with Methanosaeta, Methanosarcina, Methanoculleus, Methanospirillum and Methanobacterium; the predominating genus Methanosaeta, accounting for 40.5%, 54.2%, 73.6% and 78.7% in four samples from top to bottom, indicated a major methanogenesis pathway by acetoclastic methanogenesis in the methanogenic unit. The beta diversity indexes illustrated a more similar distribution of bacterial communities than that of methanogens between acidogenic unit and methanogenic unit. The differentiation of methanogenic community composition in two phases, as well as pH values and volatile fatty acid (VFA) concentrations confirmed the phase separation of the ITPAR. Overall, the results of this study demonstrated that the special designing of ITPAR maintained a sufficient number of methanogens, more diverse communities and stronger syntrophic associations among microorganisms, which made two phase anaerobic digestion of cellulosic materials more efficient.
摘要：
An automatic versatile system which integrated solid phase extraction (SPE) with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed. Diverse commercial SPE columns can be used under an ambient pressure in this online system realized by a dual-dilution strategy. The first dilution enabled the direct injection of complex samples with minimal pretreatment, and the second dilution realized direct introduction of large volume of strong eluent into the UHPLC column without causing peak broadening or distortion. In addition, a post-column compensation mode was also designed for the matrix-effects evaluation. The features of the online system were systematically investigated, including the dilution effect, the capture of desorption solution, the column-head stacking effect and the system recovery. Compared with the offline UHPLC system, this online system showed significant advantages such as larger injection volume, higher sensitivity, shorter analysis time and better repeatability. The feasibility of the system was demonstrated by the direct analysis of three auxins from different plant tissues, including leaves of Dracaena sanderiana, buds and petals of Bauhinia. Under the optimized conditions, the whole analysis procedure took only 7 min. All the correlation coefficients were greater than 0.9987, the limits of detection and the limits of quantitation were in the range of 0.560-0.800 ng/g and 1.80-2.60 ng/g, respectively. The recoveries of the real samples ranged from 61.0 to 117%. Finally, the post-column compensation mode was applied and no matrix-effects were observed under the analysis conditions. The automatic versatile system was rapid, sensitive and reliable. We expect this system could be extended to other target analytes in complex samples utilizing diverse SPE columns. (C) 2014 Elsevier B.V. All rights reserved.
作者机构：
[储昭升; 尹延震; 贾永见; 叶碧碧; 吴爱平] State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China;[吴爱平] Institute of Ecology, College of Bioscience and Biotechnology, Hunan Agriculture University, Changsha 410128, China;[贾永见; 程凯] College of Life Science, Central China Normal University, Wuhan 430000, China;[储昭升; 尹延震; 贾永见; 叶碧碧; 吴爱平] State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
通讯机构：
State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-environment, Chinese Research Academy of Environmental Sciences, China
作者机构：
[王得强; 陈若星; 蔡继宝; 王建兵; 罗海涛; 任周营; 倪悦; 苏加坤] Technology Center, China Tobacco Jiangxi Industrial Co., Ltd., Nanchang 330096, China;[杨虹琦] College of Bioscience and Biotechnology, Hunan Agricultural University, Key Laboratory of Tobacco Science and Health, Changsha 410128, China
通讯机构：
[Chen, R.] T;Technology Center, China Tobacco Jiangxi Industrial Co., Ltd., Nanchang 330096, China
作者机构：
[Dong, Nai-ping; Liang, Yi-Zeng; Lu, Hong-mei] Cent S Univ, Coll Chem & Chem Engn, Changsha 410083, Peoples R China.;[Xu, Qing-song] Cent S Univ, Sch Math & Stat, Changsha 410083, Peoples R China.;[Mok, Daniel K. W.] Hong Kong Polytech Univ, Dept Appl Biol & Chem Technol, Hong Kong, Hong Kong, Peoples R China.;[Mok, Daniel K. W.] State Key Lab Chinese Med & Mol Pharmacol Incubat, Shenzhen 518000, Peoples R China.;[Yi, Lun-zhao] Kunming Univ Sci & Technol, Yunnan Food Safety Res Inst, Kunming 650500, Peoples R China.
通讯机构：
[Liang, Yi-Zeng] C;Cent S Univ, Coll Chem & Chem Engn, Changsha 410083, Peoples R China.
作者机构：
[Zeng, Min; 周航; 廖柏寒; 杨文弢; 周歆; 王英杰; 刘丽] Institute of Environment Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China;[周航] College of Bioscience and Technology, Hunan Agricultural University, Changsha 410128, China
通讯机构：
Institute of Environment Science and Engineering, Central South University of Forestry and Technology, China
