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dicarboxylic acid

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https://www.readbyqxmd.com/read/28322385/dicarboxylic-acids-as-ph-sensors-for-hyperpolarized-13-c-magnetic-resonance-spectroscopic-imaging
#1
D E Korenchan, C Taglang, C von Morze, J E Blecha, J W Gordon, R Sriram, P E Z Larson, D B Vigneron, H F VanBrocklin, J Kurhanewicz, D M Wilson, R R Flavell
Imaging tumoral pH may help to characterize aggressiveness, metastasis, and therapeutic response. We report the development of hyperpolarized [2-(13)C,D10]diethylmalonic acid, which exhibits a large pH-dependent (13)C chemical shift over the physiological range. We demonstrate that co-polarization with [1-(13)C,D9]tert-butanol accurately measures pH via(13)C NMR and magnetic resonance spectroscopic imaging in phantoms.
March 21, 2017: Analyst
https://www.readbyqxmd.com/read/28321989/expansion-of-the-%C3%AF-oxidation-system-alkbgtl-of-pseudomonas-putida-gpo1-with-alkj-and-alkh-results-in-exclusive-mono-esterified-dicarboxylic-acid-production-in-e-%C3%A2-coli
#2
Youri M van Nuland, Fons A de Vogel, Gerrit Eggink, Ruud A Weusthuis
The AlkBGTL proteins coded on the alk operon from Pseudomonas putida GPo1 can selectively ω-oxidize ethyl esters of C6 to C10 fatty acids in whole-cell conversions with Escherichia coli. The major product in these conversions is the ω-alcohol. However, AlkB also has the capacity to overoxidize the substrate to the ω-aldehyde and ω-acid. In this study, we show that alcohol dehydrogenase AlkJ and aldehyde dehydrogenase AlkH are able to oxidize ω-alcohols and ω-aldehydes of esterified fatty acids respectively...
March 20, 2017: Microbial Biotechnology
https://www.readbyqxmd.com/read/28318906/analysis-of-molecular-mechanisms-of-atp-synthesis-from-the-standpoint-of-the-principle-of-electrical-neutrality
#3
REVIEW
Sunil Nath
Theories of biological energy coupling in oxidative phosphorylation (OX PHOS) and photophosphorylation (PHOTO PHOS) are reviewed and applied to ATP synthesis by an experimental system containing purified ATP synthase reconstituted into liposomes. The theories are critically evaluated from the standpoint of the principle of electrical neutrality. It is shown that the obligatory requirement to maintain overall electroneutrality of bulk aqueous phases imposes strong constraints on possible theories of energy coupling and molecular mechanisms of ATP synthesis...
March 8, 2017: Biophysical Chemistry
https://www.readbyqxmd.com/read/28291347/production-of-odd-carbon-dicarboxylic-acids-in-escherichia-coli-using-an-engineered-biotin-fatty-acid-biosynthetic-pathway
#4
Robert W Haushalter, Ryan M Phelan, Kristina M Hoh, Cindy Su, George Wang, Edward E K Baidoo, Jay D Keasling
Dicarboxylic acids are commodity chemicals used in the production of plastics, polyesters, nylons, fragrances, and medications. Bio-based routes to dicarboxylic acids are gaining attention due to environmental concerns about petroleum-based production of these compounds. Some industrial applications require dicarboxylic acids with specific carbon chain lengths, including odd-carbon species. Biosynthetic pathways involving cytochrome P450-catalyzed oxidation of fatty acids in yeast and bacteria have been reported, but these systems produce almost exclusively even-carbon species...
March 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28288640/overexpression-of-a-c4-dicarboxylate-transporter-is-the-key-for-rerouting-citric-acid-to-c4-dicarboxylic-acid-production-in-aspergillus-carbonarius
#5
Lei Yang, Eleni Christakou, Jesper Vang, Mette Lübeck, Peter Stephensen Lübeck
BACKGROUND: C4-dicarboxylic acids, including malic acid, fumaric acid and succinic acid, are valuable organic acids that can be produced and secreted by a number of microorganisms. Previous studies on organic acid production by Aspergillus carbonarius, which is capable of producing high amounts of citric acid from varieties carbon sources, have revealed its potential as a fungal cell factory. Earlier attempts to reroute citric acid production into C4-dicarboxylic acids have been with limited success...
March 14, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28280927/cuticle-ultrastructure-cuticular-lipid-composition-and-gene-expression-in-hypoxia-stressed-arabidopsis-stems-and-leaves
#6
Hyojin Kim, Dongsu Choi, Mi Chung Suh
An increased permeability of the cuticle is closely associated with downregulation of genes involved in cuticular lipid synthesis in hypoxia-stressed Arabidopsis and may allow plants to cope with oxygen deficiency. The hydrophobic cuticle layer consisting of cutin polyester and cuticular wax is the first barrier to protect the aerial parts of land plants from environmental stresses. In the present study, we investigated the role of cuticle membrane in Arabidopsis responses to oxygen deficiency. TEM analysis showed that the epidermal cells of hypoxia-treated Arabidopsis stems and leaves possessed a thinner electron-translucent cuticle proper and a more electron-dense cuticular layer...
March 9, 2017: Plant Cell Reports
https://www.readbyqxmd.com/read/28280820/tunable-white-light-emission-pmma-supported-film-materials-containing-lanthanide-coordination-polymers-preparation-characterization-and-properties
#7
Wei Chen, Ruiqing Fan, Huijie Zhang, Yuwei Dong, Ping Wang, Yulin Yang
A series of lanthanide coordination polymers(LnCPs) containing both light and heavy rare-earth elements, namely {[Eu2(pydc)3(H2O)]·2H2O}n (1-Eu, H2pydc = pyridine-2,3-dicarboxylic acid), [Ln(pyc)2(Hpyc)(NO3)]n (Ln = Nd (2-Nd), Sm (3-Sm), Eu (4-Eu), Gd (5-Gd), Tb (6-Tb), Ho (7-Ho), and Er (8-Er), Hpyc = pyridine-3-carboxylic acid), has been synthesized under hydro(solvo)thermal conditions and fully characterized. The crystal structure analysis indicates that in situ decarboxylation of H2pydc occurred in the synthesis process of 2-Nd-8-Er...
March 10, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28270441/insulin-sensitizer-prevents-and-ameliorates-experimental-type-1-diabetes
#8
Michael Valitsky, Amnon Hoffman, Terry Unterman, Jacob Bar-Tana
Insulin-dependent type-1 diabetes (T1D) is driven by autoimmune beta-cell failure, whereas systemic resistance to insulin is considered the hallmark of insulin-independent type-2 diabetes (T2D). In contrast to this canonical dichotomy, insulin resistance appears to precede the overt diabetic stage of T1D and to predict its progression, implying that insulin sensitizers may change the course of T1D. However, previous attempts to ameliorate T1D in animal models or patients by insulin sensitizers have largely failed...
March 7, 2017: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28268250/antioxidant-effect-of-thiazolidine-molecules-in-cell-culture-media-improves-stability-and-performance
#9
Jennifer Kuschelewski, Alisa Schnellbaecher, Sascha Pering, Maria Wehsling, Aline Zimmer
The ability of cell culture media components to generate reactive species as well as their sensitivity to oxidative degradation, affects the overall stability of media and the behavior of cells cultured in vitro. This study investigates the influence of thiazolidine molecules, formed from the condensation between cysteine and alpha-ketoacids, on the stability of these complex mixtures and on the performance of cell culture processes aiming to produce therapeutically relevant monoclonal antibodies. Results presented in this study indicate that 2-methyl-1,3-thiazolidine-2,4-dicarboxylic acid and 2-(2-carboxyethyl)-1,3-thiazolidine-2,4-dicarboxylic acid, obtained by condensation of cysteine with pyruvate or alpha-ketoglutarate respectively, are able to stabilize cell culture media formulations, in particular redox sensitive molecules like folic acid, thiamine, L-methionine (met) and L-tryptophan (trp)...
March 7, 2017: Biotechnology Progress
https://www.readbyqxmd.com/read/28261242/identification-and-functional-characterization-of-a-tonoplast-dicarboxylate-transporter-in-tomato-solanum-lycopersicum
#10
Ruiling Liu, Boqiang Li, Guozheng Qin, Zhanquan Zhang, Shiping Tian
Acidity plays an important role in flavor and overall organoleptic quality of fruit and is mainly due to the presence of organic acids. Understanding the molecular basis of organic acid metabolism is thus of primary importance for fruit quality improvement. Here, we cloned a putative tonoplast dicarboxylate transporter gene (SlTDT) from tomato, and submitted it to the NCBI database (GenBank accession number: KC733165). SlTDT protein contained 13 putative transmembrane domains in silico analysis. Confocal microscopic study using green fluorescent fusion proteins revealed that SlTDT was localized on tonoplast...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28251204/robust-high-connected-rare-earth-mofs-as-efficient-heterogeneous-catalysts-for-co2-conversion
#11
Na Wei, Rong-Xia Zuo, Yu-Yang Zhang, Zheng-Bo Han, Xue-Jun Gu
Two series of chemically and thermally stable rare-earth MOFs were constructed using trinuclear [M3(μ3-OH)(COO)6] SBUs and linear dicarboxylate linkers, which feature three-dimensional 12-connected frameworks with an hcp topology. These materials contain a large density of Lewis acidic sites, leading to high catalytic activity towards the cycloaddition of CO2 and epoxides under mild conditions.
March 18, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28245117/octadentate-zirconium-iv-loaded-macrocycles-with-varied-stoichiometry-assembled-from-hydroxamic-acid-monomers-using-metal-templated-synthesis
#12
William Tieu, Tulip Lifa, Andrew Katsifis, Rachel Codd
The reaction between Zr(IV) and the forward endo-hydroxamic acid monomer 4-[(5-aminopentyl)(hydroxy)amino]-4-oxobutanoic acid (for-PBH) in a 1:4 stoichiometry in the presence of diphenylphosphoryl azide and triethylamine gave the octadentate Zr(IV)-loaded tetrameric hydroxamic acid macrocycle for-[Zr(DFOT1)] ([M + H](+) calc 887.3, obs 887.2). In this metal-templated synthesis (MTS) approach, the coordination preferences of Zr(IV) directed the preorganization of four oxygen-rich bidentate for-PBH ligands about the metal ion prior to ring closure under peptide coupling conditions...
February 28, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28240331/a-multi-responsive-luminescent-sensor-for-organic-small-molecule-pollutants-and-metal-ions-based-on-a-4d-4f-metal-organic-framework
#13
Huili Ma, Lu Wang, Jinghuo Chen, Xuejing Zhang, Liang Wang, Na Xu, Guangming Yang, Peng Cheng
Two silver(i)-lanthanide(iii) heterometallic-organic frameworks (HMOFs) {[Ln3Ag3(BPDC)5(OX)(H2O)7]·7H2O}n (Ln = Tb (1), Gd (2)) have been synthesized via a mixed ligand approach using 2,2'-bipyridine-3,3'-dicarboxylic acid (H2BPDC) and oxalic acid (H2OX) under hydrothermal conditions. Single crystal X-ray diffraction studies showed a (3,4,5)-connected new topology of {3·4(2)·5·6(2)}{3·4(3)·5(2)·6(3)·7}{3·5·6(2)·9·10}{4(2)·5·6(3)}{4(2)·5}{4(2)·6}{4(3)·5·6(2)}{4(3)·6(3)}{4(3)·6(4)·8(2)·10}...
March 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28235876/comparison-of-biochemical-properties-of-the-original-and-newly-identified-oleate-hydratases-from-stenotrophomonas-maltophilia
#14
Woo-Ri Kang, Min-Ju Seo, Kyung-Chul Shin, Jin-Byung Park, Deok-Kun Oh
Oleate hydratases (OhyAs) catalyze the conversion of unsaturated fatty acids to 10-hydroxy fatty acids, which are used as precursors of important industrial compounds, including lactones, and ω-hydroxycarboxylic and α,ω-dicarboxylic acids. The genes encoding OhyA and a putative fatty acid hydratase in Stenotrophomonas maltophilia were identified by genomic analysis. The putative fatty acid hydratase was purified and identified as an oleate hydratase (OhyA2) based on its substrate specificity. The activity of OhyA2 as a holoenzyme was not affected on adding cofactors, whereas the activity of the original oleate hydratase (OhyA1) showed an increase...
February 24, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28229207/engineering-rtca-pathway-and-c4-dicarboxylate-transporter-for-l-malic-acid-production
#15
Xiulai Chen, Yuancai Wang, Xiaoxiang Dong, Guipeng Hu, Liming Liu
L-Malic acid is an important component of a vast array of food additives, antioxidants, disincrustants, pharmaceuticals, and cosmetics. Here, we presented a pathway optimization strategy and a transporter modification approach to reconstruct the L-malic acid biosynthesis pathway and transport system, respectively. First, pyruvate carboxylase (pyc) and malate dehydrogenase (mdh) from Aspergillus flavus and Rhizopus oryzae were combinatorially overexpressed to construct the reductive tricarboxylic acid (rTCA) pathway for L-malic acid biosynthesis...
February 22, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28221797/acid-gas-adsorption-on-metal-organic-framework-nanosheets-as-a-model-of-an-all-surface-material
#16
Joshua D Howe, Yang Liu, Luis Flores, David A Dixon, David S Sholl
To establish a model of metal-organic framework (MOF) surfaces and build an understanding of surface-specific ligand adsorption phenomena in MOFs, we present a computational study exploring multiple models of a series of MOF-2 nanosheet materials, "M-BDCs", with M = Zn, Cu, and Co and BDC = benzene-1,4-dicarboxylate. We study and assess the appropriateness of a series of models ranging from small clusters (18 atoms) to fully periodic sheet models. We additionally study the interactions of these models with acid gases and energy-relevant small molecules (CO, CO2, H2O, SO2, NO2, and H2S)...
March 14, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28218544/direct-imide-formation-from-thiophene-dicarboxylic-acids-gives-expanded-side-chain-selection-in-thienopyrrolediones
#17
Rylan M W Wolfe, John R Reynolds
The synthesis of thienopyrroledione (TPD) has been updated to reduce the number of synthetic steps, remove hazardous and toxic reagents, reduce the amount of byproduct waste, and reduce the use of solvents when unnecessary. Diverse functionalization is possible, introducing 16 examples in yields from 34% to 95%. This reaction scheme was shown to be general for thiophene imides, and a more thorough exploration into side chain engineering is presented with TPD acceptors often used in organic electronic applications...
February 20, 2017: Organic Letters
https://www.readbyqxmd.com/read/28217111/integration-of-metagenomic-and-stable-carbon-isotope-evidence-reveals-the-extent-and-mechanisms-of-carbon-dioxide-fixation-in-high-temperature-microbial-communities
#18
Ryan de Montmollin Jennings, James J Moran, Zackary J Jay, Jacob P Beam, Laura M Whitmore, Mark A Kozubal, Helen W Kreuzer, William P Inskeep
Although the biological fixation of CO2 by chemolithoautotrophs provides a diverse suite of organic compounds utilized by chemoorganoheterotrophs as a carbon and energy source, the relative amounts of autotrophic C in chemotrophic microbial communities are not well-established. The extent and mechanisms of CO2 fixation were evaluated across a comprehensive set of high-temperature, chemotrophic microbial communities in Yellowstone National Park by combining metagenomic and stable (13)C isotope analyses. Fifteen geothermal sites representing three distinct habitat types (iron-oxide mats, anoxic sulfur sediments, and filamentous "streamer" communities) were investigated...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28211689/a-stable-porphyrin-based-porous-mog-metal-organic-framework-as-an-efficient-solvent-free-catalyst-for-c-c-bond-formation
#19
Wei Jiang, Jin Yang, Ying-Ying Liu, Shu-Yan Song, Jian-Fang Ma
We herein report the porous 4-fold interpenetrated mog (moganite) metal-organic framework (MOF) [Cd3(tipp)(bpdc)2]·DMA·9H2O (1·Cd; H2tipp = 5,10,15,20-tetrakis(4-(imidazol-1-yl)phenyl)porphyrin, H2bpdc = biphenyl-4,4'-dicarboxylic acid, DMA = N,N'-dimethylacetamide). The incorporation of Cd and carboxylate oxygen affords 1·Cd rich Lewis acid and basic sites. This MOF 1·Cd was then applied as an efficient heterogeneous catalyst for the important cyanosilylation of aldehydes and Knoevenagel condensation reactions...
February 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28198811/%C3%AE-thalassemia-patients-revealed-a-significant-change-of-untargeted-metabolites-in-comparison-to-healthy-individuals
#20
Syed Ghulam Musharraf, Ayesha Iqbal, Saqib Hussain Ansari, Sadia Parveen, Ishtiaq Ahmad Khan, Amna Jabbar Siddiqui
β-Thalassemia is one of the most prevalent forms of congenital blood disorders characterized by reduced hemoglobin levels with severe complications, affecting all dimensions of life. The mechanisms underlying the phenotypic heterogeneity of β-thalassemia are still poorly understood. We aimed to work over metabolite biomarkers to improve mechanistic understanding of phenotypic heterogeneity and hence better management of disorder at different levels. Untargeted serum metabolites were analyzed after protein precipitation and SPE (solid phase extraction) from 100 β-thalassemia patients and 61 healthy controls using GC-MS...
February 13, 2017: Scientific Reports
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