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Nicolai Kallscheuer, Jan Marienhagen
BACKGROUND: Hydroxybenzoic acids are industrially relevant aromatic compounds, which also play key roles in the microbial carbon metabolism, e.g., as precursors for the synthesis of cofactors or metal-chelating molecules. Due to its pronounced resistance to aromatics Corynebacterium glutamicum represents an interesting platform for production of these compounds. Unfortunately, a complex catabolic network for aromatic molecules prevents application of C. glutamicum for microbial production of aromatic compounds other than aromatic amino acids, which cannot be metabolized by this microorganism...
May 12, 2018: Microbial Cell Factories
Artur Conde, Andreia Neves, Richard Breia, Diana Pimentel, Lia-Tânia Dinis, Sara Bernardo, Carlos Manuel Correia, Ana Cunha, Hernâni Gerós, José Moutinho-Pereira
Water scarcity is associated with extreme temperatures and high irradiance, and significantly and increasingly affects grapevine yield and quality. In this context, the foliar application of kaolin, a chemically inert mineral that greatly reflects ultraviolet and infrared radiations, as well as, in part, photosynthetically active radiation, has recently been shown to decrease photoinhibition in mature leaves. Here, the influence of this particle film on grapevine leaf metabolome and carbohydrate metabolism was evaluated...
April 2018: Journal of Plant Physiology
Giuseppe Cassone, Jiri Sponer, Judit E Sponer, Fabio Pietrucci, A Marco Saitta, Franz Saija
The formation of the first C-C bonds from formaldehyde represents the rate-limiting step of the formose reaction. However, the free-energy surface associated with such a process has never been determined in condensed phase. By means of ab initio molecular dynamics and metadynamics techniques here we report on the free-energy landscape underlying the synthesis of glycolaldehyde from a formaldehyde aqueous solution. Moreover, numerical samples of formaldehyde (both neat and in water solution) and of glycolaldehyde (both neat and in aqueous solution) have been exposed to intense electric fields...
March 27, 2018: Chemical Communications: Chem Comm
Alexander Klaus, Tim Baldensperger, Roman Fiedler, Matthias Girndt, Marcus A Glomb
In the present study, we investigated the role of transketolase (TK) in the modulation of glycolaldehyde driven Maillard reactions. In vitro experiments with recombinant human TK reduced glycolaldehyde and glyoxal induced carbonyl stress and thereby suppressed the formation of advanced glycation endproducts up to 70% due to the enzyme-catalyzed conversion of glycolaldehyde to erythrulose. This was further substantiated by the use of 13 C-labeled compounds. For the first time, glycolaldehyde and other sugars involved in the TK reaction were quantified in vivo and compared to nondiabetic uremic patients undergoing hemodialysis...
February 14, 2018: Journal of Agricultural and Food Chemistry
Chun-Fang Li, Jian-Qiang Ma, Dan-Juan Huang, Chun-Lei Ma, Ji-Qiang Jin, Ming-Zhe Yao, Liang Chen
Albino tea cultivars are special mutants of tea plants with white or yellow leaf color. In this study, three albino tea cultivars, including 'Anji Baicha', 'Huangjinya', and 'Baijiguan', and two green tea cultivars, 'Longjing 43' and 'Fuding Dabaicha', were applied to metabolite profiling by gas chromatography-mass spectrometry and ultraperformance liquid chromatography-mass spectrometry. Multivariate analyses revealed significantly different metabolite phenotypes in leaves among albino cultivars and green cultivars...
February 28, 2018: Journal of Agricultural and Food Chemistry
Markus Draskovits, Christian Stanetty, Ian R Baxendale, Marko D Mihovilovic
The acyloxyallylation of unprotected aldoses was first demonstrated more than a decade ago as a potentially elegant two-carbon homologation of reducing sugars (upon ozonolysis); however, its application in real case syntheses remained scarce. Following up on such a successful showcase and to answer several pending questions about this attractive transformation, we engaged in an in depth methodological reinvestigation. The epimeric tetroses l-erythrose and d-threose in unprotected and protected form were successfully applied to the indium and also zinc-mediated acyloxyallylation, with the latter being a first for an unprotected sugar...
March 2, 2018: Journal of Organic Chemistry
Liangzhi Li, Pei Kang, Xin Ju, Jiajia Chen, Huibin Zou, Cuiying Hu, Lishi Yan
Erythritol, a well-known natural sweetener, is mainly produced by microbial fermentation. Various metal ions (Al3+ , Cu2+ , Mn2+ , and Ni2+ ) were added to the culture medium of Trichosporonoides oedocephalis ATCC 16958 at 30 mg/L in shake flask cultures. Compared with controls, Cu2+ increased the erythritol content by 86% and decreased the glycerol by-product by 31%. After 48 hr of shake flask culture, sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that expression levels of erythrose reductase (ER) in the presence of 30 mg/L CuSO4  · 5H2 O were higher than those obtained after treatment with other examined metal ions...
March 16, 2018: Preparative Biochemistry & Biotechnology
Jikun Du, Dongsoo Yang, Zi Wei Luo, Sang Yup Lee
Indirubin is an indole alkaloid that can be used to treat various diseases including granulocytic leukemia, cancer, and Alzheimer's disease. Microbial production of indirubin has so far been achieved by supplementation of rather expensive substrates such as indole or tryptophan. Here, we report the development of metabolically engineered Escherichia coli strain capable of producing indirubin directly from glucose. First, the Methylophaga aminisulfidivorans flavin-containing monooxygenase (FMO) and E. coli tryptophanase (TnaA) were introduced into E...
February 10, 2018: Journal of Biotechnology
Ines Loureiro, Joana Faria, Nuno Santarem, Terry K Smith, Joana Tavares, Anabela Cordeiro-da-Silva
The trypanosomatids, Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp, are causative agents of important human diseases such African sleeping sickness, Chagas' disease and Leishmaniasis, respectively. The high impact of these diseases on human health and economy worldwide, the unsatisfactory available chemotherapeutic options and the absence of human effective vaccines, strongly justifies the search for new drugs. The pentose phosphate pathway has been proposed to be a viable strategy to defeat several infectious diseases, including those from trypanosomatids, as it includes an oxidative branch, important in the maintenance of cell redox homeostasis, and a non-oxidative branch in which ribose 5-phosphate and erythrose 4-phosphate, precursors of nucleic acids and aromatic amino acids, are produced...
December 5, 2017: Current Medicinal Chemistry
Samy Boulos, Laura Nyström
The oxidation of cereal (1→3,1→4)-β-D-glucan can influence the health promoting and technological properties of this linear, soluble homopolysaccharide by introduction of new functional groups or chain scission. Apart from deliberate oxidative modifications, oxidation of β-glucan can already occur during processing and storage, which is mediated by hydroxyl radicals (HO• ) formed by the Fenton reaction. We present four complementary sample preparation strategies to investigate oat and barley β-glucan oxidation products by hydrophilic interaction ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), employing selective enzymatic digestion, graphitized carbon solid phase extraction (SPE), and functional group labeling techniques...
2017: Frontiers in Chemistry
T C Mamedes-Rodrigues, D S Batista, N M Vieira, E M Matos, D Fernandes, A Nunes-Nesi, C D Cruz, L F Viccini, F T S Nogueira, W C Otoni
Brachypodium distachyon, a model species for forage grasses and cereal crops, has been used in studies seeking improved biomass production and increased crop yield for biofuel production purposes. Somatic embryogenesis (SE) is the morphogenetic pathway that supports in vitro regeneration of such species. However, there are gaps in terms of studies on the metabolic profile and genetic stability along successive subcultures. The physiological variables and the metabolic profile of embryogenic callus (EC) and embryogenic structures (ES) from successive subcultures (30, 60, 90, 120, 150, 180, 210, 240, and 360-day-old subcultures) were analyzed...
March 2018: Protoplasma
Niamh M Denihan, Jennifer A Kirwan, Brian H Walsh, Warwick B Dunn, David I Broadhurst, Geraldine B Boylan, Deirdre M Murray
Elucidating metabolic effects of hypoxic-ischaemic encephalopathy (HIE) may reveal early biomarkers of injury and new treatment targets. This study uses untargeted metabolomics to examine early metabolic alterations in a carefully defined neonatal population. Infants with perinatal asphyxia who were resuscitated at birth and recovered (PA group), those who developed HIE (HIE group) and healthy controls were all recruited at birth. Metabolomic analysis of cord blood was performed using direct infusion FT-ICR mass spectrometry...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
Siew Bee Tang, Jana C Lee, Jin Kyo Jung, Man-Yeon Choi
Previously, we studied various combinations of non-nutritive sugars including erythritol and erythrose having a potentially insecticidal effect on Drosophila suzukii. The study suggested two potential physiological changes causing fly mortality: 1) starvation from the feeding of non-metabolizable erythritol and erythrose; 2) abnormal osmotic pressure increased in the hemolymph with erythritol transported from the midgut. In the present study, sucrose and erythritol were applied to blueberries and effects of these combinations on fly mortality and fecundity were monitored in the lab and greenhouse...
August 2017: Journal of Insect Physiology
Xingxing Zou, Jinping Lin, Xinlei Mao, Shengyun Zhao, Yuhong Ren
L-erythrose, a rare aldotetrose, possesses various pharmacological activities. However, efficient L-erythrose production is challenging. Currently, L-erythrose is produced by a two-step fermentation process from erythritol. Here, we describe a novel strategy for the production of L-erythrose in Gluconobacter oxydans (G. oxydans) by localizing the assembly of L-ribose isomerase (L-RI) to membrane-bound sorbitol dehydrogenase (SDH) via the protein-peptide interactions of the PDZ domain and PDZ ligand. To demonstrate this self-assembly, green fluorescent protein (GFP) replaced L-RI and its movement to membrane-bound SDH was observed by fluorescence microscopy...
September 6, 2017: Journal of Agricultural and Food Chemistry
Ina Häuslein, Franck Cantet, Sarah Reschke, Fan Chen, Matteo Bonazzi, Wolfgang Eisenreich
The human pathogen Coxiella burnetii causes Q-fever and is classified as a category B bio-weapon. Exploiting the development of the axenic growth medium ACCM-2, we have now used 13 C-labeling experiments and isotopolog profiling to investigate the highly diverse metabolic network of C. burnetii . To this aim, C. burnetii RSA 439 NMII was cultured in ACCM-2 containing 5 mM of either [U-13 C3 ]serine, [U-13 C6 ]glucose, or [U-13 C3 ]glycerol until the late-logarithmic phase. GC/MS-based isotopolog profiling of protein-derived amino acids, methanol-soluble polar metabolites, fatty acids, and cell wall components (e...
2017: Frontiers in Cellular and Infection Microbiology
Tomasz Janek, Adam Dobrowolski, Anna Biegalska, Aleksandra M Mirończuk
BACKGROUND: Erythritol is a natural sweetener that is used in the food industry. It is produced as an osmoprotectant by bacteria and yeast. Due to its chemical properties, it does not change the insulin level in the blood, and therefore it can be safely used by diabetics. Previously, it has been shown that erythrose reductase (ER), which catalyzes the final step, plays a crucial role in erythritol synthesis. ER reduces erythrose to erythritol with NAD(P)H as a cofactor. Despite many studies on erythritol synthesis by Yarrowia lipolytica, the enzymes involved in this metabolic pathway have ever been described...
July 11, 2017: Microbial Cell Factories
Luigi Da Vià, Carlo Recchi, Thomas E Davies, Nicholas Greeves, Jose A Lopez-Sanchez
The visible-light-mediated photo-catalytic selective valorisation of glucose using TiO2-supported Ag nanoparticles is shown for the first time. The optimisation of the catalyst composition, substrate-to-catalyst ratio and reaction medium proved that a near total suppression of the mineralisation pathway could be achieved with a selectivity to partial oxidation products and small-chain monosaccharides as high as 98 %. The primary products were determined to be gluconic acid, arabinose, erythrose, glyceraldehyde and formic acid...
November 22, 2016: ChemCatChem
Man-Yeon Choi, Siew Bee Tang, Seung-Joon Ahn, Kaushalya G Amarasekare, Peter Shearer, Jana C Lee
In this study, we investigated the effects of non-nutritive sugars and sugar alcohols on the survivorship of spotted wing drosophila, Drosophila suzukii, and found erythritol and erythrose as potentially insecticidal to the fly. In a dose-dependent study, erythritol and erythrose significantly reduced fly longevity, with 100% mortality with 1, 0.5, 0.1 & 0.05M doses after feeding for 7days. When sucrose and erythritol solutions were provided separately to flies for 7days, there was no effect on survivorship regardless of erythritol concentrations...
May 2017: Journal of Insect Physiology
Sun-Mi Shin, Thinh-Phat Cao, Jin Myung Choi, Seong-Bo Kim, Sang-Jae Lee, Sung Haeng Lee, Dong-Woo Lee
There is currently little information on nonphosphorylated sugar epimerases, which are of potential interest for producing rare sugars. We found a gene (the TM0416 gene) encoding a putative d-tagatose-3-epimerase-related protein from the hyperthermophilic bacterium Thermotoga maritima We overexpressed the TM0416 gene in Escherichia coli and purified the resulting recombinant protein for detailed characterization. Amino acid sequence alignment and a structural similarity search revealed that TM0416 is a putative nonphosphorylated sugar epimerase...
May 15, 2017: Applied and Environmental Microbiology
Ulrich Weininger
NMR-spectroscopy enables unique experimental studies on protein dynamics at atomic resolution. In order to obtain a full atom view on protein dynamics, and to study specific local processes like ring-flips, proton-transfer, or tautomerization, one has to perform studies on amino-acid side chains. A key requirement for these studies is site-selective labeling with13 C and/or1 H, which is achieved in the most general way by using site-selectively13 C-enriched glucose (1- and 2-13 C) as the carbon source in bacterial expression systems...
March 2017: Journal of Biomolecular NMR
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