The Experts below are selected from a list of 3123 Experts worldwide ranked by ideXlab platform
Byoung-in Sang - One of the best experts on this subject based on the ideXlab platform.
-
Optimization of Hexanoic Acid production in recombinant Escherichia coli by precise flux rebalancing.
Bioresource Technology, 2017Co-Authors: Sungho Jang, Byoung Seung Jeon, Byoung-in Sang, Gyoo Yeol JungAbstract:Abstract The aim of this study is to demonstrate that rebalancing of metabolic fluxes at acetyl-CoA branch node can substantially improve the titer and productivity of Hexanoic Acid in recombinant Escherichia coli strains. First, a Hexanoic Acid-producing E. coli strain was constructed by expressing genes encoding β-ketothiolase (BktB) from Cupriavidus necator and acetyl-CoA transferase (ACT) from Megasphaera sp. MH in a butyric Acid producer strain. Next, metabolic flux was optimized at the acetyl-CoA branch node by fine-tuning the expression level of the gene for acetyl-CoA acetyltransferase (AtoB). Four synthetic 5′-untranslated regions were designed for atoB using UTR Designer to modulate the expression level of the gene. Notably, the productivity of the optimized strain (14.7 mg/L/h) was the highest among recombinant E. coli strains in literature when using a similar inoculum size for fermentation. These results show that fine-tuning the expression level of atoB is critical for production of Hexanoic Acid.
-
In Situ Biphasic Extractive Fermentation for Hexanoic Acid Production from Sucrose by Megasphaera elsdenii NCIMB 702410
Applied Biochemistry and Biotechnology, 2013Co-Authors: Kieun Choi, Byoung Seung Jeon, Byung-chun Kim, Byoung-in SangAbstract:Hexanoic Acid production by a bacterium using sucrose as an economic carbon source was studied under conditions in which Hexanoic Acid was continuously extracted by liquid–liquid extraction. Megasphaera elsdenii NCIMB 702410, selected from five M . elsdenii strains, produced 4.69 g l^−1 Hexanoic Acid in a basal medium containing sucrose. Production increased to 8.19 g l^−1 when the medium was supplemented by 5 g l^−1 sodium butyrate. A biphasic liquid–liquid extraction system with 10 % ( v / v ) alamine 336 in oleyl alcohol as a solvent was evaluated in a continuous stirred-tank reactor held at pH 6. Over 90 % ( w / w ) of the Hexanoic Acid in a 0.5 M aqueous solution was transferred to the extraction solvent within 10 h. Cell growth was not significantly inhibited by direct contact of the fermentation broth with the extraction solvent. The system produced 28.42 g l^−1 of Hexanoic Acid from 54.85 g l^−1 of sucrose during 144 h of culture, and 26.52 and 1.90 g l^−1 of Hexanoic Acid was accumulated in the extraction solvent and the aqueous fermentation broth, respectively. The productivity and yield of Hexanoic Acid were 0.20 g l^−1 h^−1 and 0.50 g g^−1 sucrose, respectively.
-
in situ extractive fermentation for the production of Hexanoic Acid from galactitol by clostridium sp bs 1
Enzyme and Microbial Technology, 2013Co-Authors: Byoung Seung Jeon, Youngsoon Um, Byoung-in Sang, Chuloo MoonAbstract:Abstract Clostridium sp. BS-1 produces Hexanoic Acid as a metabolite using galactitol and enhanced Hexanoic Acid production was obtained by in situ extractive fermentation with Clostridium sp. BS-1 under an optimized medium composition. For medium optimization, five ingredients were selected as variables, and among them yeast extract, tryptone, and sodium butyrate were selected as significant variables according to a fractional factorial experimental design, a steepest ascent experimental design, and a Box–Behnken experimental design. The optimized medium had the following compositions in modified Clostridium acetobutyricum (mCAB) medium: 15.5 g L−1 of yeast extract, 10.13 g L−1 of tryptone, 0.04 g L−1 of FeSO4·7H2O, 0.85 g L−1 of sodium acetate, and 6.47 g L−1 of sodium butyrate. The predicted concentration of Hexanoic Acid with the optimized medium was 6.98 g L−1, and this was validated experimentally by producing 6.96 g L−1 of Hexanoic Acid with Clostridium sp. BS-1 under the optimized conditions. In situ extractive fermentation for Hexanoic Acid removal was then applied in a batch culture system with the optimized medium and 10% (v/v) alamine 336 in oleyl alcohol as an extractive solvent. The pH of the culture in the extractive fermentation was maintained at 5.4–5.6 by an Acid balance between production and retrieval by extraction. During a 16 day culture, the Hexanoic Acid concentration in the solvent increased to 32 g L−1 while it was maintained in a range of 1–2 g L−1 in the medium. The maximum rate of Hexanoic Acid production was 0.34 g L−1 h−1 in in situ extractive fermentation.
-
production of Hexanoic Acid from d galactitol by a newly isolated clostridium sp bs 1
Applied Microbiology and Biotechnology, 2010Co-Authors: Byoung Seung Jeon, Youngsoon Um, Byoung-in SangAbstract:In a study screening anaerobic microbes utilizing d-galactitol as a fermentable carbon source, four bacterial strains were isolated from an enrichment culture producing H2, ethanol, butanol, acetic Acid, butyric Acid, and Hexanoic Acid. Among these isolates, strain BS-1 produced Hexanoic Acid as a major metabolic product of anaerobic fermentation with d-galactitol. Strain BS-1 belonged to the genus Clostridium based on phylogenetic analysis using 16S rRNA gene sequences, and the most closely related strain was Clostridium sporosphaeroides DSM 1294T, with 94.4% 16S rRNA gene similarity. In batch cultures, Clostridium sp. BS-1 produced 550 ± 31 mL L−1 of H2, 0.36 ± 0.01 g L−1 of acetic Acid, 0.44 ± 0.01 g L−1 of butyric Acid, and 0.98 ± 0.03 g L−1 of Hexanoic Acid in a 4-day cultivation. The production of Hexanoic Acid increased to 1.22 and 1.73 g L−1 with the addition of 1.5 g L−1 of sodium acetate and 100 mM 2-(N-morpholino)ethanesulfonic Acid (MES), respectively. Especially when 1.5 g L−1 of sodium acetate and 100 mM MES were added simultaneously, the production of Hexanoic Acid increased up to 2.99 g L−1. Without adding sodium acetate, 2.75 g L−1 of Hexanoic Acid production from d-galactitol was achieved using a coculture of Clostridium sp. BS-1 and one of the isolates, Clostridium sp. BS-7, in the presence of 100 mM MES. In addition, volatile fatty Acid (VFA) production by Clostridium sp. BS-1 from d-galactitol and d-glucose was enhanced when a more reduced culture redox potential (CRP) was applied via addition of Na2S·9H2O.
Thomas Henle - One of the best experts on this subject based on the ideXlab platform.
-
identification and quantitation of the lipation product 2 amino 6 3 methylpyridin 1 ium 1 yl Hexanoic Acid mp lysine in peanuts
Journal of Agricultural and Food Chemistry, 2016Co-Authors: Martin Globisch, Meike Deuber, Thomas HenleAbstract:The lipid peroxidation product acrolein was semiquantitated by GC-MS (EI) in unheated and heated peanut oil, respectively, representing a model system for peanut roasting. Depending on the heating time, acrolein levels significantly increased from 0.2 to 10.7 mg/kg oil. As a result of heating Nα-acetyl-l-lysine and acrolein, the pyridinium derivative 2-acetamido-6-(3-methylpyridin-1-ium-1-yl)Hexanoic Acid (MP-acetyl lysine) was identified. In addition, the lysine derivative 2-amino-6-[5-(hydroxymethyl)-3,6-dihydro-2H-pyridin-1-yl]Hexanoic Acid was identified after reduction and hydrolysis. After preparation of 2-amino-6-(3-methylpyridin-1-ium-1-yl)Hexanoic Acid (MP-lysine) as reference material, its amounts were quantitated in acrolein-modified peanut proteins by HPLC-ESI-MS/MS after Acid hydrolysis, showing that at low acrolein concentrations, the modification of lysine could be entirely explained by the formation of MP-lysine. Furthermore, for the first time, MP-lysine was quantitated in peanut samples ...
-
Identification and Quantitation of the Lipation Product 2‑Amino-6-(3-methylpyridin-1-ium-1-yl)Hexanoic Acid (MP-Lysine) in Peanuts
2016Co-Authors: Martin Globisch, Meike Deuber, Thomas HenleAbstract:The lipid peroxidation product acrolein was semiquantitated by GC-MS (EI) in unheated and heated peanut oil, respectively, representing a model system for peanut roasting. Depending on the heating time, acrolein levels significantly increased from 0.2 to 10.7 mg/kg oil. As a result of heating Nα-acetyl-l-lysine and acrolein, the pyridinium derivative 2-acetamido-6-(3-methylpyridin-1-ium-1-yl)Hexanoic Acid (MP-acetyl lysine) was identified. In addition, the lysine derivative 2-amino-6-[5-(hydroxymethyl)-3,6-dihydro-2H-pyridin-1-yl]Hexanoic Acid was identified after reduction and hydrolysis. After preparation of 2-amino-6-(3-methylpyridin-1-ium-1-yl)Hexanoic Acid (MP-lysine) as reference material, its amounts were quantitated in acrolein-modified peanut proteins by HPLC-ESI-MS/MS after Acid hydrolysis, showing that at low acrolein concentrations, the modification of lysine could be entirely explained by the formation of MP-lysine. Furthermore, for the first time, MP-lysine was quantitated in peanut samples in amounts up to 10.2 mg/kg, showing an increase depending on the roasting time. Thus, MP-lysine might represent a marker to evaluate the extent of food protein lipation by acrolein
Joyce A Reid - One of the best experts on this subject based on the ideXlab platform.
-
synthesis of the hydroxyethylene dipeptide isostere 2s 4s 5s 5 amino 6 cyclohexyl 4 hydroxy 2 isopropyl Hexanoic Acid n butyl amide
Tetrahedron Letters, 1992Co-Authors: Michael A Poss, Joyce A ReidAbstract:Abstract A stereoselective synthesis of the hydroxyethylene dipeptide isostere, (2S,4S,5S)-5-amino-6-cyclohexyl-4-hydroxy-2-isopropyl Hexanoic Acid n-butyl amide from Boc-L-phenylalanine is described.
Carmen Gonzalezbosch - One of the best experts on this subject based on the ideXlab platform.
-
Hexanoic Acid treatment prevents systemic mnsv movement in cucumis melo plants by priming callose deposition correlating sa and opda accumulation
Frontiers in Plant Science, 2017Co-Authors: Emma Fernandezcrespo, Pilar Garciaagustin, Ivan Finiti, Jose A Navarro, Marta Serrasoriano, Vicente Pallas, Carmen GonzalezboschAbstract:Unlike fungal and bacterial diseases, no direct method is available to control viral diseases. The use of resistance-inducing compounds can be an alternative strategy for plant viruses. Here we studied the basal response of melon to Melon necrotic spot virus (MNSV) and demonstrated the efficacy of Hexanoic Acid (Hx) priming, which prevents the virus from systemically spreading. We analysed callose deposition and the hormonal profile and gene expression at the whole plant level. This allowed us to determine hormonal homeostasis in the melon roots, cotyledons, hypocotyls, stems and leaves involved in basal and Hexanoic Acid-induced resistance (Hx-IR) to MNSV. Our data indicate important roles of salicylic Acid (SA), 12-oxo-phytodienoic Acid (OPDA), jasmonic-isoleucine, and ferulic Acid in both responses to MNSV. The hormonal and metabolites balance, depending on the time and location associated with basal and Hx-IR, demonstrated the reprogramming of plant metabolism in MNSV-inoculated plants. The treatment with both SA and OPDA prior to virus infection significantly reduced MNSV systemic movement by inducing callose deposition. This demonstrates their relevance in Hx-IR against MNSV and a high correlation with callose deposition. Our data also provide valuable evidence to unravel priming mechanisms by natural compounds.
-
Hexanoic Acid treatment prevents systemic mnsv movement in cucumis melo plants by priming callose deposition correlating sa and opda accumulation
Frontiers in Plant Science, 2017Co-Authors: Emma Fernandezcrespo, Pilar Garciaagustin, Ivan Finiti, Jose A Navarro, Marta Serrasoriano, Vicente Pallas, Carmen GonzalezboschAbstract:Abstract Unlike fungal and bacterial diseases, no direct method is available to control viral diseases. The use of resistance-inducing compounds can be an alternative strategy for plant viruses. Here we studied the basal response of melon to Melon necrotic spot virus (MNSV) and demonstrated the efficacy of Hexanoic Acid (Hx) priming, which prevents the virus from systemically spreading. We analysed callose deposition and the hormonal profile and gene expression at the whole plant level. This allowed us to determine hormonal homeostasis in the melon roots, cotyledons, hypocotyls, stems and leaves involved in basal and Hexanoic Acid-induced resistance (Hx-IR) to MNSV. We also demonstrated the relevant roles of salicylic Acid (SA), 12-oxo-phytodienoic Acid (OPDA), jasmonic-isoleucine (JA-Ile) and ferulic Acid in both responses to MNSV. The hormonal and metabolites balance, depending on the time and location associated with basal and Hx-IR, demonstrated the reprogramming of plant metabolism in MNSV-inoculated plants. The treatment with both SA and OPDA prior to virus infection significantly reduced MNSV systemic movement by inducing callose deposition. This demonstrates their relevance in Hx-IR against MNSV and a high correlation with callose deposition. Our data also provide valuable evidence to unravel priming mechanisms by natural compounds.
-
oxylipin mediated stress response of a miraculin like protease inhibitor in Hexanoic Acid primed eggplant plants infested by colorado potato beetle
Journal of Plant Physiology, 2017Co-Authors: Jose M Lopezgaliano, Victor M Ruizarroyo, Emma Fernandezcrespo, Carolina Rausell, Dolores M Real, Pilar Garciaagustin, Carmen Gonzalezbosch, Inmaculada GarciaroblesAbstract:Insect-plant interactions are governed by a complex equilibrium between the mechanisms through which plant recognize insect attack and orchestrate downstream signaling events that trigger plant defense responses, and the mechanisms by which insects overcome plant defenses. Due to this tight and dynamic interplay, insight into the nature of the plant defense response can be gained by analyzing changes in the insect herbivores digestive system upon plant feeding. In this work we have identified a Solanum melongena miraculin-like protease inhibitor in the midgut juice of Colorado potato larvae feeding on eggplant plants treated with the natural inducer of plant defenses Hexanoic Acid. We analyzed the corresponding gene expression by qRT-PCR and our results showed that this eggplant miraculin-like gene enhanced induction contributes to the Hexanoic Acid priming effect in this Solanaceae species. Moreover, our data evidencing that OPDA might be involved in this gene regulation highlights its potential as biomarker in eggplant plant responses to stress mediated this oxylipin signaling pathway.
-
role of dioxygenase α dox2 and sa in basal response and in Hexanoic Acid induced resistance of tomato solanum lycopersicum plants against botrytis cinerea
Journal of Plant Physiology, 2015Co-Authors: Carlos Angulo, Emma Fernandezcrespo, Pilar Garciaagustin, Maria De La O Leyva, Ivan Finiti, Jaime Lopezcruz, Carmen GonzalezboschAbstract:Resistance of tomato (Solanum Lycopersicum) to the fungal pathogen Botrytis cinerea requires complex interplay between hormonal signalling. In this study, we explored the involvement of new oxylipins in the tomato basal and induced response to this necrotroph through the functional analysis of the tomato α-dioxygenase2 (α-DOX2)-deficient mutant divaricata. We also investigated the role of SA in the defence response against this necrotrophic fungus using SA-deficient tomato nahG plants. The plants lacking dioxigenase α-DOX2, which catalyses oxylipins production from fatty Acids, were more susceptible to Botrytis, and Hexanoic Acid-induced resistance (Hx-IR) was impaired; hence α-DOX2 is required for both tomato defence and the enhanced protection conferred by natural inducer Hexanoic Acid (Hx) against B. cinerea. The divaricata plants accumulated less pathogen-induced callose and presented lower levels of jasmonic Acid (JA) and 12-oxo-phytodienoic Acid (OPDA) upon infection if compared to the wild type. Glutathion-S-transferase (GST) gene expression decreased and ROS production significantly increased in Botrytis-infected divaricata plants. These results indicate that absence of α-DOX2 influences the hormonal changes, oxidative burst and callose deposition that occur upon Botrytis infection in tomato. The study of SA-deficient nahG tomato plants showed that the plants with low SA levels displayed increased resistance to Botrytis, but were unable to display Hx-IR. This supports the involvement of SA in Hx-IR. NaghG plants displayed reduced callose and ROS accumulation upon infection and an increased GST expression. This reflects a positive relationship between SA and these defensive mechanisms in tomato. Finally, Hx boosted the pathogen-induced callose in nahG plants, suggesting that this priming mechanism is SA-independent. Our results support the involvement of the oxylipins pathway and SA in tomato response to Botrytis, probably through complex crosstalk of the hormonal balance with callose and ROS accumulation, and reinforce the role of the oxidative stress in the outcome of the plant-Botrytis interaction.
-
priming of plant resistance by natural compounds Hexanoic Acid as a model
Frontiers in Plant Science, 2014Co-Authors: Paz Aranegabou, Pilar Garciaagustin, Maria De La O Leyva, Ivan Finiti, Carmen GonzalezboschAbstract:Some alternative control strategies of currently emerging plant diseases are based on the use of resistance inducers. This review highlights the recent advances made in the characterization of natural compounds that induce resistance by a priming mechanism. These include vitamins, chitosans, oligogalacturonides, volatile organic compounds, azelaic and pipecolic Acid, among others. Overall, other than providing novel disease control strategies that meet environmental regulations, natural priming agents are valuable tools to help unravel the complex mechanisms underlying the induced resistance phenomenon. The data presented in this review reflect the novel contributions made from studying these natural plant inducers, with special emphasis placed on Hexanoic Acid (Hx), proposed herein as a model tool for this research field. Hx is a potent natural priming agent of proven efficiency in a wide range of host plants and pathogens. It can early activate broad-spectrum defenses by inducing callose deposition and the SA and JA pathways. Later it can prime pathogen-specific responses according to the pathogen’s lifestyle. Interestingly, Hx primes redox-related genes to produce an anti-oxidant protective effect, which might be critical for limiting the infection of necrotrophs. Our Hx-induced resistance (Hx-IR) findings also strongly suggest that it is an attractive tool for the molecular characterization of the plant alarmed state, with the added advantage of it being a natural compound.
Elisabeth Davioudcharvet - One of the best experts on this subject based on the ideXlab platform.
-
a fluoro analogue of the menadione derivative 6 2 3 methyl 1 4 naphthoquinolyl Hexanoic Acid is a suicide substrate of glutathione reductase crystal structure of the alkylated human enzyme
Journal of the American Chemical Society, 2006Co-Authors: Holger Bauer, Karin Fritzwolf, Andreas Winzer, Sebastian Kuhner, Bruce A Palfey, Heiner R Schirmer, Vanessa Yardley, Hervé Vezin, Susan J. Little, Elisabeth DavioudcharvetAbstract:Glutathione reductase is an important housekeeping enzyme for redox homeostasis both in human cells and in the causative agent of tropical malaria, Plasmodium falciparum. Glutathione reductase inhibitors were shown to have anticancer and antimalarial activity per se and to contribute to the reversal of drug resistance. The development of menadione chemistry has led to the selection of 6-[2‘-(3‘-methyl)-1‘,4‘-naphthoquinolyl]Hexanoic Acid, called M5,as a potent reversible and uncompetitive inhibitor of both human and P. falciparum glutathione reductases. Here we describe the synthesis and kinetic characterization of a fluoromethyl-M5 analogue that acts as a mechanism-based inhibitor of both enzymes. In the course of enzymatic catalysis, the suicide substrate is activated by one- or two-electron reduction, and then a highly reactive quinone methide is generated upon elimination of the fluorine. Accordingly the human enzyme was found to be irreversibly inactivated with a kinact value of 0.4 ± 0.2 min-1. The ...