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https://www.readbyqxmd.com/read/28221022/quantitative-13c-traces-of-glucose-fate-in-hepatitis-b-virus-infected-hepatocytes
#1
Qianfen Wan, Yulan Wang, Huiru Tang
Quantitative characterization of 13C-labeled metabolites is an important part of the stable isotope tracing method widely used in metabolic flux analysis. Due to long relaxation time and low sensitivity of 13C nuclei, direct measurement of 13C labeled metabolites using one dimensional 13C NMR often fails to meet the demand of metabolomics studies especially with large number of samples and metabolites having low abundance. Although HSQC-based 2D NMR methods have improved sensitivity with inversion detection, they are time-consuming thus unsuitable for high-throughput absolute quantification of 13C-labeled metabolites...
February 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28220832/water-use-efficiency-of-an-old-growth-forest-in-lower-subtropical-china
#2
Xiaodong Liu, Xiuzhi Chen, Ronghua Li, Fengling Long, Lu Zhang, Qianmei Zhang, Jiyue Li
Carbon and water fluxes are key properties of ecosystem processes and functions. A better understanding of their temporal dynamics and coupling mechanism between these fluxes will help us improve ecosystem management for mitigation as well as adaption to future climatic change. From 2003 to 2009, carbon and water flux data were obtained by the eddy covariance method over an old-growth forest in the lower subtropical China. The 7 years of observational data indicated that the water-use efficiency (WUE) of the old-growth forest exhibited weak inter-annual variability...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28218815/glycoengineering-of-esterase-activity-through-metabolic-flux-based-modulation-of-sialic-acid
#3
Mohit Mathew, Elaine Tan, Jason W Labonte, Shivam Shah, Christopher T Saeui, Lingshu Liu, Rahul Bhattacharya, Patawut Bovonratwet, Jeffrey J Gray, Kevin Yarema
This report describes the metabolic glycoengineering (MGE) of intracellular esterase activity in human colon cancer (LS174T) and Chinese hamster ovary (CHO) cells. In silico analysis of the carboxylesterases CES1 and CES2 suggested that these enzymes are modified with sialylated N-glycans, which are proposed to stabilize the active multimeric forms of these enzymes. This premise was supported by treating cells with butanolylated ManNAc to increase sialylation, which in turn increased esterase activity. By contrast, hexosamine analogs not targeted to sialic acid biosynthesis (e...
February 20, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28217351/k1-2x-ni1-x-fe2-aso4-3-x-0-125-un-nouvel-ars%C3%A3-niate-%C3%A3-structure-de-type-%C3%AE-crpo4
#4
Ridha Ben Smail, Mohamed Faouzi Zid
A new arsenate K1+2x Ni1-x Fe2(AsO4)3 (x = 1/8) {potassium nickel diiron(III) tris-[arsenate(V)]} was synthesized using a flux method and its crystal structure was determined from single-crystal X-ray diffraction data. This material was also characterized by qualitative energy dispersive X-ray spectroscopy (EDS) analysis. The crystal structure belongs to the α-CrPO4-structure type, space group Imma. It consists of a three-dimensional-framework built up from FeO6 and Ni0.875□1.25O6-octa-hedra and AsO4-tetra-hedra that are sharing corners and/or edges, generating tunnels running along the [010] and [001] directions in which the potassium cations are located...
February 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28214874/heat-acclimation-regulates-the-autophagy-lysosome-function-to-protect-against-heat-stroke-induced-brain-injury-in-mice
#5
Junfeng Yi, Genlin He, Ju Yang, Zhen Luo, Xuesen Yang, Xue Luo
BACKGROUND/AIMS: The mechanisms underlying the protective role of heat acclimation (HA) in heat stroke (HS)-induced brain injury are still unclear. The autophagy-lysosome pathway is known to pay an important role in protecting stressed or diseased cells from death. Nevertheless, whether autophagy and lysosomes are involved in HA-mediated neuroprotection following HS exposure remains unclear. METHODS: The protective effects of HA were assessed by rectal temperature, hematoxylin-eosin staining, transmission electron microscopic analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining, and Fluoro Jade B staining, after mice were subjected to HS...
January 18, 2017: Cellular Physiology and Biochemistry
https://www.readbyqxmd.com/read/28214847/contribution-of-p62-to-phenotype-transition-of-coronary-arterial-myocytes-with-defective-autophagy
#6
Junxiang Bao, Guangbi Li, Xinxu Yuan, Erich Gulbins, Pin-Lan Li
BACKGROUND: Autophagy disorder contributes to dedifferentiation of arterial smooth muscle cells, but the mechanisms are poorly understood. Here, we sought to investigate the role of scaffolding adaptor p62/SQSTM1 (p62) in phenotype switching of mouse coronary arterial myocytes (CAMs) induced by CD38 gene deficiency or lysosomal dysfunction which blocks autophagic flux in the cells. METHODS: Protein expression was measured by western blot analysis and immunofluorescent staining...
3, 2017: Cellular Physiology and Biochemistry
https://www.readbyqxmd.com/read/28214117/evaluating-carbon-fluxes-of-global-forest-ecosystems-by-using-an-individual-tree-based-model-forcchn
#7
Jianyong Ma, Herman H Shugart, Xiaodong Yan, Cougui Cao, Shuang Wu, Jing Fang
The carbon budget of forest ecosystems, an important component of the terrestrial carbon cycle, needs to be accurately quantified and predicted by ecological models. As a preamble to apply the model to estimate global carbon uptake by forest ecosystems, we used the CO2 flux measurements from 37 forest eddy-covariance sites to examine the individual tree-based FORCCHN model's performance globally. In these initial tests, the FORCCHN model simulated gross primary production (GPP), ecosystem respiration (ER) and net ecosystem production (NEP) with correlations of 0...
February 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28213705/responses-of-soil-methanogens-methanotrophs-and-methane-fluxes-to-land-use-conversion-and-fertilization-in-a-hilly-red-soil-region-of-southern-china
#8
Huifeng Liu, Xing Wu, Zongshan Li, Qing Wang, Dan Liu, Guohua Liu
Changes in land-uses and fertilization are important factors regulating methane (CH4) emissions from paddy soils. However, the responses of soil CH4 emissions to these factors and the underlying mechanisms remain unclear. The objective of this study was to explore the effects of land-use conversion from paddies to orchards and fertilization on soil CH4 fluxes, and the abundance and community compositions of methanogens and methanotrophs. Soil CH4 fluxes were quantified by static chamber and gas chromatography technology...
February 17, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28213171/13c-labeling-analysis-of-sugars-by-high-resolution-mass-spectrometry-for-metabolic-flux-analysis
#9
Sébastien Acket, Anthony Degournay, Franck Merlier, Brigitte Thomasset
Metabolic flux analysis is particularly complex in plant cells because of highly compartmented metabolism. Analysis of free sugars is interesting because it provides data to define fluxes around hexose, pentose, and triose phosphate pools in different compartment. In this work, we present a method to analyze the isotopomer distribution of free sugars labeled with carbon 13 using a liquid chromatography-high resolution mass spectrometry, without derivatized procedure, adapted for Metabolic flux analysis. Our results showed a good sensitivity, reproducibility and better accuracy to determine isotopic enrichments of free sugars compared to our previous methods [5, 6]...
February 14, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/28212377/optimality-principles-reveal-a-complex-interplay-of-intermediate-toxicity-and-kinetic-efficiency-in-the-regulation-of-prokaryotic-metabolism
#10
Jan Ewald, Martin Bartl, Thomas Dandekar, Christoph Kaleta
A precise and rapid adjustment of fluxes through metabolic pathways is crucial for organisms to prevail in changing environmental conditions. Based on this reasoning, many guiding principles that govern the evolution of metabolic networks and their regulation have been uncovered. To this end, methods from dynamic optimization are ideally suited since they allow to uncover optimality principles behind the regulation of metabolic networks. We used dynamic optimization to investigate the influence of toxic intermediates in connection with the efficiency of enzymes on the regulation of a linear metabolic pathway...
February 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28208489/prediction-of-the-moments-in-advection-diffusion-lattice-boltzmann-method-ii-attenuation-of-the-boundary-layers-via-double-%C3%AE-bounce-back-flux-scheme
#11
Irina Ginzburg
Impact of the unphysical tangential advective-diffusion constraint of the bounce-back (BB) reflection on the impermeable solid surface is examined for the first four moments of concentration. Despite the number of recent improvements for the Neumann condition in the lattice Boltzmann method-advection-diffusion equation, the BB rule remains the only known local mass-conserving no-flux condition suitable for staircase porous geometry. We examine the closure relation of the BB rule in straight channel and cylindrical capillary analytically, and show that it excites the Knudsen-type boundary layers in the nonequilibrium solution for full-weight equilibrium stencil...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208315/tracer-counterpermeation-analysis-of-diffusivity-in-finite-length-nanopores-with-and-without-single-file-dynamics
#12
David M Ackerman, James W Evans
We perform a tracer counterpermeation (TCP) analysis for a stochastic model of diffusive transport through a narrow linear pore where passing of species within the pore is inhibited or even excluded (single-file diffusion). TCP involves differently labeled but otherwise identical particles from two decoupled infinite reservoirs adsorbing into opposite ends of the pore, and desorbing from either end. In addition to transient behavior, we assess steady-state concentration profiles, spatial correlations, particle number fluctuations, and diffusion fluxes through the pore...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208288/-15-n-nmr-based-approach-for-amino-acids-based-13-c-metabolic-flux-analysis-of-metabolism
#13
Pierre Millard, Edern Cahoreau, Maud Heuillet, Jean-Charles Portais, Guy Lippens
NMR analysis of the isotope incorporation in amino acids can be used to derive information about the topology and operation of cellular metabolism. Although traditionally performed by (1)H and/or (13)C NMR, we present here novel experiments that exploit the (15)N nucleus to derive the same information with increased efficiency. Combined with a novel Hα-(13)CO experiment, we increase the coverage of the isotopic space that can be probed by obtaining the complete distribution of isotopic species for the first two carbons of amino acids in cellular biomass hydrolysates...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28207249/convection-driven-pull-down-assays-in-nanoliter-droplets-using-scaffolded-aptamers
#14
Xiangmeng Qu, Hongbo Zhang, Hong Chen, Ali Aldalbahi, Li Li, Yang Tian, David A Weitz, Hao Pei
One of the great challenges in cellular studies is to develop a rapid and biocompatible analytical tool for single-cell analysis. We report a rapid, DNA nanostructure-supported aptamer pull-down (DNaPull) assay under convective flux in a glass capillary for analyzing contents of droplets with nano or picoliter volumes. We have demonstrated that the scaffolded aptamer can greatly improve the efficiency of target molecules' pull-down. The convective flux enables complete reaction in less than 5 min, which is an 18-fold improvement compared to purely diffusive flux (traditional model of stationary case)...
February 16, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28202180/chemical-structure-influence-on-napl-mixture-nonideality-evolution-rate-limited-dissolution-and-contaminant-mass-flux
#15
Mark C Padgett, Geoffrey R Tick, Kenneth C Carroll, William R Burke
The influence of chemical structure on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux was examined. The variability of measured and UNIFAC modeled NAPL activity coefficients as a function of mole fraction was compared for two NAPL mixtures containing structurally-different contaminants of concern including toluene (TOL) or trichloroethene (TCE) within a hexadecane (HEXDEC) matrix. The results showed that dissolution from the NAPL mixtures transitioned from ideality for mole fractions >0...
February 3, 2017: Journal of Contaminant Hydrology
https://www.readbyqxmd.com/read/28199086/crystal-growth-and-structure-analysis-of-ce18w10o57-a-complex-oxide-containing-tungsten-in-an-unusual-trigonal-prismatic-coordination-environment
#16
Dileka Abeysinghe, Mark D Smith, Jeongho Yeon, T Thao Tran, Robert Paria Sena, Joke Hadermann, P Shiv Halasyamani, Hans-Conrad Zur Loye
The noncentrosymmetric tungstate oxide, Ce18W10O57, was synthesized for the first time as high-quality single crystals via the molten chloride flux method and structurally characterized by single-crystal X-ray diffraction. The compound is a structural analogue to the previously reported La18W10O57, which crystallizes in the hexagonal space group P6̅2c. The +3 oxidation state of cerium in Ce18W10O57 was achieved via the in situ reduction of Ce(IV) to Ce(III) using Zn metal. The structure consists of both isolated and face-shared WO6 octahedra and, surprisingly, isolated WO6 trigonal prisms...
February 15, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28196685/geochemical-analysis-of-sediments-from-a-semi-enclosed-bay-dongshan-bay-southeast-china-to-determine-the-anthropogenic-impact-and-source
#17
Yonghang Xu, Qinqin Sun, Xiang Ye, Xijie Yin, Dongyi Li, Liang Wang, Aijun Wang, Yunhai Li
The geochemical compositions of sediments in the Dongshan Bay, a semi-enclosed bay on the southeast coast of China, were obtained to identify pollutant sources and evaluate the anthropogenic impacts over the last 100 years. The results indicated that the metal flux had been increasing since the 1980s. Enrichment factor values (Pb, Zn and Cu) suggested only slight enrichment. The proportion of anthropogenic Pb changed from 9% to 15% during 2000-2014. Coal combustion might be an important contamination source in the Dongshan Bay...
January 17, 2017: Chemosphere
https://www.readbyqxmd.com/read/28194224/carbon-uptake-by-mature-amazon-forests-has-mitigated-amazon-nations-carbon-emissions
#18
Oliver L Phillips, Roel J W Brienen
BACKGROUND: Several independent lines of evidence suggest that Amazon forests have provided a significant carbon sink service, and also that the Amazon carbon sink in intact, mature forests may now be threatened as a result of different processes. There has however been no work done to quantify non-land-use-change forest carbon fluxes on a national basis within Amazonia, or to place these national fluxes and their possible changes in the context of the major anthropogenic carbon fluxes in the region...
December 2017: Carbon Balance and Management
https://www.readbyqxmd.com/read/28193001/coalescence-sampling-and-analysis-of-aerosols-using-aerosol-optical-tweezers
#19
Allen E Haddrell, Rachael E H Miles, Bryan R Bzdek, Jonathan P Reid, Rebecca J Hopkins, Jim S Walker
We present a first exploratory study to assess the use of aerosol optical tweezers as an instrument for sampling and detecting accumulation- and coarse-mode aerosol. A subpicoliter aqueous aerosol droplet is captured in the optical trap and used as a sampling volume, accreting mass from a free-flowing aerosol generated by a medical nebulizer or atomizer. Real-time measurements of the initial stability in size, refractive index, and composition of the sampling droplet inferred from Raman spectroscopy confirm that these quantities can be measured with high accuracy and low noise...
February 9, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28192496/impact-of-nitrogen-fertilization-on-soil-atmosphere-greenhouse-gas-exchanges-in-eucalypt-plantations-with-different-soil-characteristics-in-southern-china
#20
Kai Zhang, Hua Zheng, Falin Chen, Ruida Li, Miao Yang, Zhiyun Ouyang, Jun Lan, Xuewu Xiang
Nitrogen (N) fertilization is necessary to sustain productivity in eucalypt plantations, but it can increase the risk of greenhouse gas emissions. However, the response of soil greenhouse gas emissions to N fertilization might be influenced by soil characteristics, which is of great significance for accurately assessing greenhouse gas budgets and scientific fertilization in plantations. We conducted a two-year N fertilization experiment (control [CK], low N [LN], middle N [MN] and high N [HN] fertilization) in two eucalypt plantations with different soil characteristics (higher and lower soil organic carbon sites [HSOC and LSOC]) in Guangxi, China, and assessed soil-atmosphere greenhouse gas exchanges...
2017: PloS One
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