Structural basis for the allosteric pathway of 4-amino-4-deoxychorismate synthase.

4-Amino-4-deoxychorismate synthase (ADCS), a chorismate-utilizing enzyme, is composed of two subunits: PabA and PabB. PabA is a glutamine amidotransferase that hydrolyzes glutamine into glutamate and ammonia. PabB is an aminodeoxychorismate synthase that converts chorismate to 4-amino-4-deoxychorismate (ADC) using the ammonia produced by PabA.

A functionally uncharacterized type-2 malate/L-lactate dehydrogenase family protein from Thermus thermophilus HB8 catalyzes stereospecific reduction of 2-keto-3-deoxy-D-gluconate.

2-Keto-3-deoxy- D-gluconate (KDG) is an important intermediate found in various sugars, sugar acids and polysaccharide catabolic pathways. Here, we report that a functionally uncharacterized type-2 malate/L-lactate dehydrogenase family protein (TTHB078) from Thermus thermophilus HB8 catalyzes a novel reaction, NAD(P)H-dependent reductase activity on KDG. This enzyme, designated KdgG, utilizes both NADH and NADPH as electron donors, but higher activity was observed with NADH.

Arabidopsis NPF5.1 regulates ABA homeostasis and seed germination by mediating ABA uptake into the seed coat.

Abscisic acid (ABA) is a plant hormone that induces seed dormancy during seed development and inhibits seed germination after imbibition. Although ABA is synthesized in the seed coat (testa), endosperm, and embryo, the physiological roles of the hormone derived from each tissue are not fully understood. We found that the gene encoding an Arabidopsis ABA importer, , was expressed in the seed coat during seed development.

Identification and Molecular Characterization of the Operon Required for L-Asparagine Utilization in .

Understanding the metabolic pathways of amino acids and their regulation is important for the rational metabolic engineering of amino acid production. The catabolic pathways of L-asparagine and L-aspartate are composed of transporters for amino acid uptake and asparaginase and aspartase, which are involved in the sequential deamination to fumarate. However, knowledge of the catabolic genes for asparagine in bacteria of the Actinobacteria class has been limited.

Membrane Reactor for Methanol Synthesis Using Si-Rich LTA Zeolite Membrane.

We successfully demonstrated the effect of a membrane reactor for methanol synthesis to improve one-pass CO conversion. An Si-rich LTA membrane for dehydration from a methanol synthesis reaction field was synthesized by the seed-assisted hydrothermal synthesis method. The HO permselective performance of the membrane showed 1.

Bench-Scale Membrane Reactor for Methylcyclohexane Dehydrogenation Using Silica Membrane Module.

Methylcyclohexane-toluene system is one of the most promising methods for hydrogen transport/storage. The methylcyclohexane dehydrogenation can be exceeded by the equilibrium conversion using membrane reactor. However, the modularization of the membrane reactor and manufacturing longer silica membranes than 100 mm are little developed.

The Gene Encoding Fermentative l-Lactate Dehydrogenase in Is Positively Regulated by the Global Regulator GlxR.

Bacterial metabolism shifts from aerobic respiration to fermentation at the transition from exponential to stationary growth phases in response to limited oxygen availability. , a Gram-positive, facultative aerobic bacterium used for industrial amino acid production, excretes l-lactate, acetate, and succinate as fermentation products. The gene encoding l-lactate dehydrogenase is solely responsible for l-lactate production.

Enhancement of CO Adsorption/Desorption Properties of Solid Sorbents Using Tetraethylenepentamine/Diethanolamine Blends.

Mesocellular silica foam was impregnated with tetraethylenepentamine (TEPA), diethanolamine (DEA), and their mixtures and examined as sorbents for CO capture. The sorbents were characterized by N physisorption, elemental analysis, and Fourier transform infrared spectroscopy. The effects of amine blending on the CO uptake, working capacity, and heat of adsorption were investigated and discussed.

Swelling Phenomena of the Nonswelling Clay Induced by CO and Water Cooperative Adsorption in Janus-Surface Micropores.

With the development of microscopy and sensor techniques, it becomes evident that nonswelling clays show swelling behavior under CO-water mixture environments at high pressures and temperatures. The examples include Illite, muscovite, and kaolinite-rich rock samples. Here, we investigated the underlying mechanisms of kaolinite swelling induced by CO and water using molecular simulations and low-pressure gas adsorption experiments.

Effect of Carbonic Anhydrase on CO Separation Performance of Thin Poly(amidoamine) Dendrimer/Poly(ethylene glycol) Hybrid Membranes.

The effect of carbonic anhydrase (CA) on the separation performance of thin poly(amidoamine) (PAMAM) dendrimer/poly(ethylene glycol) (PEG) hybrid membranes was investigated. CA, a type of enzyme, was used to promote CO hydration and dehydration reactions and to assess whether these reactions were the rate-limiting step in CO permeation through the membrane. The relationship between the membrane thickness and the CO permeance was evaluated in CO/H or CO/He separation using PAMAM/PEG hybrid membranes (thickness: 10-100 μm) with and without CA.

Development of CVD Silica Membranes Having High Hydrogen Permeance and Steam Durability and a Membrane Reactor for a Water Gas Shift Reaction.

Water gas shift reaction of carbon monoxide (CO) with membrane reactors should be a promising method for hydrogen mass-production because of its high CO conversion, high hydrogen purity and low carbon dioxide emission. For developing such membrane reactors, we need hydrogen permselective membranes with high hydrogen permeance with order of 10 mol m s Pa at 573 K and high steam durability. In this study, we have optimized the kind of substrates, precursors, vapor concentration, and chemical vapor deposition (CVD) time using the counter-diffusion CVD method for developing such membranes.

Production of 4-Hydroxybenzoic Acid by an Aerobic Growth-Arrested Bioprocess Using Metabolically Engineered Corynebacterium glutamicum.

was metabolically engineered to produce 4-hydroxybenzoic acid (4-HBA), a valuable aromatic compound used as a raw material for the production of liquid crystal polymers and paraben. was found to have a higher tolerance to 4-HBA toxicity than previously reported hosts used for the production of genetically engineered 4-HBA. To obtain higher titers of 4-HBA, we employed a stepwise overexpression of all seven target genes in the shikimate pathway in Specifically, multiple chromosomal integrations of a mutated gene from , encoding a 3-deoxy-d-arabinoheptulosonic acid 7-phosphate (DAHP) synthase, and wild-type from , encoding chorismate synthase, shikimate kinase, and 3-dehydroquinate synthase, were effective in increasing product titers.

Extracytoplasmic function sigma factor σ confers resistance to environmental stress by enhancing mycolate synthesis and modifying peptidoglycan structures in Corynebacterium glutamicum.

Mycolates are α-branched, β-hydroxylated, long-chain fatty acid specifically synthesized in bacteria in the suborder Corynebacterineae of the phylum Actinobacteria. They form an outer membrane, which functions as a permeability barrier and confers pathogenic mycobacteria to resistance to antibiotics. Although the mycolate biosynthetic pathway has been intensively studied, knowledge of transcriptional regulation of genes involved in this pathway is limited.

Comparison of Solvation Effects on CO Capture with Aqueous Amine Solutions and Amine-Functionalized Ionic Liquids.

Amines are the most widely utilized chemicals for postcombustion CO capture, because the reversible reactions between amines and CO through their moderate interaction allow effective "catch and release". Usually, CO is dissolved in the form of an anion such as carbamate or bicarbonate. Therefore, the reaction energy diagram is potentially governed to a large extent by the polarity of the surrounding solvent.

Colorimetric pH Measurement of Pressurized Groundwater Containing CO2.

A gas-tight pH measurement is needed to monitor water chemistry at a CO2 geological storage site. In the CO2 reservoirs, the temperature and pressure are generally more than the critical point of CO2 (31.2°C and 7.

The extracytoplasmic function σ factor σ(C) regulates expression of a branched quinol oxidation pathway in Corynebacterium glutamicum.

Bacteria modify their expression of different terminal oxidases in response to oxygen availability. Corynebacterium glutamicum, a facultative anaerobic bacterium of the phylum Actinobacteria, possesses aa3 -type cytochrome c oxidase and cytochrome bd-type quinol oxidase, the latter of which is induced by oxygen limitation. We report that an extracytoplasmic function σ factor, σ(C) , is responsible for the regulation of this process.

The uncertainty of climate sensitivity and its implication for the Paris negotiation.

Uncertainty of climate sensitivity is one of the critical issues that may affect climate response strategies. Whereas the equilibrium climate sensitivity (ECS) was specified as 2-4.5 °C with the best estimate of 3 °C in the 4th Assessment Report of IPCC, it was revised to 1.

The increased CO2 adsorption performance of chitosan-derived activated carbons with nitrogen-doping.

Highly porous nitrogen-doped activated carbons (NACs) were prepared by the chemical activation of chitosan using alkali carbonates. The NACs exhibited extremely high CO2 capacities of 1.6 mmol g(-1) (15 kPa) and 4.

Overexpression of the phosphofructokinase encoding gene is crucial for achieving high production of D-lactate in Corynebacterium glutamicum under oxygen deprivation.

We previously reported on the impacts of the overexpression of individual genes of the glycolytic pathway encoding glucokinase (GLK), glyceraldehyde phosphate dehydrogenase (GAPDH), phosphofructokinase (PFK), triosephosphate isomerase (TPI), and bisphosphate aldolase (FBA) on D-lactate productivity in Corynebacterium glutamicum under oxygen-deprived conditions. Searching for synergies, in the current study, we simultaneously overexpressed the five glycolytic genes in a stepwise fashion to evaluate the effect of the cumulative overexpression of glycolytic genes on D-lactate production. Interestingly, the final D-lactate concentration markedly differed depending on whether or not the PFK encoding gene was overexpressed when combined with overexpressing other glycolytic genes.

Glucose consumption rate critically depends on redox state in Corynebacterium glutamicum under oxygen deprivation.

Rapid sugar consumption is important for the microbial production of chemicals and fuels. Here, we show that overexpression of the NADH dehydrogenase gene (ndh) increased glucose consumption rate in Corynebacterium glutamicum under oxygen-deprived conditions through investigating the relationship between the glucose consumption rate and intracellular NADH/NAD(+) ratio in various mutant strains. The NADH/NAD(+) ratio was strongly repressed under oxygen deprivation when glucose consumption was accelerated by the addition of pyruvate or sodium hydrogen carbonate.

Individual and combined roles of malonichrome, ferricrocin, and TAFC siderophores in Fusarium graminearum pathogenic and sexual development.

Intra- and extracellular iron-chelating siderophores produced by fungal non-ribosomal peptide synthetases have been shown to be involved in reproductive and pathogenic developmental processes and in iron and oxidative stress management. Here we report individual and combined contributions of three of these metabolites to developmental success of the destructive cereal pathogen Fusarium graminearum. In previous work, we determined that deletion of the NPS2 gene, responsible for intracellular siderophore biosynthesis, results in inability to produce sexual spores when mutants of this homothallic ascomycete are selfed.

Effect of Cross-Linking on the Mechanical and Thermal Properties of Poly(amidoamine) Dendrimer/Poly(vinyl alcohol) Hybrid Membranes for CO2 Separation.

Poly(amidoamine) (PAMAM) dendrimers were incorporated into cross-linked poly(vinyl alcohol) (PVA) matrix to improve carbon dioxide (CO2) separation performance at elevated pressures. In our previous studies, PAMAM/PVA hybrid membranes showed high CO2 separation properties from CO2/H2 mixed gases. In this study, three types of organic Ti metal compounds were selected as PVA cross-linkers that were used to prepare PAMAM/cross-linked PVA hybrid membranes.

Chorismate-dependent transcriptional regulation of quinate/shikimate utilization genes by LysR-type transcriptional regulator QsuR in Corynebacterium glutamicum: carbon flow control at metabolic branch point.

The qsu operon of Corynebacterium glutamicum comprises four genes (qsuABCD) that underpin the microorganism's quinate/shikimate utilization pathways. The genes encode enzymes that catalyse reactions at the metabolic branch point between the biosynthesis route for synthesis of aromatic compounds and the catabolic route for degradation of quinate and shikimate for energy production. A qsuR gene located immediately upstream of qsuA encodes a protein (QsuR) which activates the operon in the presence of quinate or shikimate.