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Metabolic disorders including obesity, diabetes and non-alcoholic steatohepatitis are a group of conditions characterised by chronic low-grade inflammation of metabolic tissues. There is now a growing appreciation that various metabolites released from adipose tissue serve as key signalling mediators, influencing this interaction with inflammation. G protein-coupled receptors (GPCRs) are the largest family of signal transduction proteins and most historically successful drug targets. The signalling pathways for several key adipose metabolites are mediated through GPCRs expressed both on the adipocytes themselves and on infiltrating macrophages. These include three main groups of GPCRs: the FFA4 receptor, which is activated by long chain free fatty acids; the HCA2 and HCA3 receptors, activated by hydroxy carboxylic acids; and the succinate receptor. Understanding the roles these metabolites and their receptors play in metabolic-immune interactions is critical to establishing how these GPCRs may be exploited for the treatment of metabolic disorders. [ABSTRACT FROM AUTHOR]

Metabolic disorders including obesity, diabetes and non-alcoholic steatohepatitis are a group of conditions characterised by chronic low-grade inflammation of metabolic tissues. There is now a growing appreciation that various metabolites released from adipose tissue serve as key signalling mediators, influencing this interaction with inflammation. G protein-coupled receptors (GPCRs) are the largest family of signal transduction proteins and most historically successful drug targets. The signalling pathways for several key adipose metabolites are mediated through GPCRs expressed both on the adipocytes themselves and on infiltrating macrophages. These include three main groups of GPCRs: the FFA4 receptor, which is activated by long chain free fatty acids; the HCA2 and HCA3 receptors, activated by hydroxy carboxylic acids; and the succinate receptor. Understanding the roles these metabolites and their receptors play in metabolic-immune interactions is critical to establishing how these GPCRs may be exploited for the treatment of metabolic disorders.

Highlights • Recovery and purification of hydroxy acids from alkaline black liquors is studied. • Hydroxy acids are efficiently purified with a sequential chromatographic process. • The process enables the recycling of lignin and spent pulping chemicals as such. • The separation materials used have a low fouling tendency. Abstract In this study, an efficient sequential chromatographic process for recovering hydroxy acids (HAs) from soda and kraft black liquors (BLs) has been developed. Lignin and pulping chemicals are also recovered and can be recycled back to the pulping process. A weak cation exchange resin in Na+ form separates lignin from BL. Up to 95% lignin yield was obtained, with over 50% yield for HAs as Na salts. A cellulose-based resin is used to separate HAs from NaOH. Complete separation, and thus 100% yield for HAs and NaOH, was achieved. The HAs in soda BL are liberated by ion exchange. In case of kraft BL, the solution is acidified with H 2 SO 4 and subjected to ion exchange and ion exclusion chromatography to recover the remaining pulping chemicals. It was found that fouling, which limits the efficiency of membrane-based processing of BLs, is avoided with the appropriate choice of chromatographic separation materials. [ABSTRACT FROM AUTHOR]

A novel approach to synthesize enantiomerically pure α-hydroxy carboxylic derivatives is reported. A highly stereoselective oxidation of titanium(IV) enolates from chiral N-acyloxazolidinones is performed with oxygen under simple experimental conditions that do not require any reducing steps. The success of this approach depends on the biradical character of titanium(IV) enolates. [ABSTRACT FROM AUTHOR]

Abstract: Fumaric acid esters (FAEs) such as dimethylfumarate (DMF) are used for the treatment of adults with moderate‐to‐severe psoriasis. The mode of action of FAEs is complex. Here, we provide a comprehensive review of the literature to describe the molecular mechanisms by which DMF and its active metabolite monomethylfumarate (MMF) exert their anti‐inflammatory and immune modulatory effects. MMF can bind to the hydroxy‐carboxylic acid receptor 2 (HCA2) on the cell surface and both DMF and MMF react with intracellular glutathione following cell penetration. DMF and to some extent also MMF modulate the activity of certain cellular signalling proteins such as the nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2), nuclear factor kappa B (Nf‐κB) and the cellular concentration of cyclic adenosine monophosphate. Some studies show that DMF can also affect the hypoxia‐inducible factor 1‐alpha (HIF‐1α). These actions seem to be responsible for i) the downregulation of inflammatory cytokines and ii) an overall shift from a proinflammatory Th1/Th17 response to an anti‐inflammatory/regulatory Th2 response. Both steps are necessary for the amelioration of psoriatic inflammation, although additional mechanisms have been proposed. There is a growing body of evidence to support the notion that DMF/MMF may also exert effects on granulocytes and non‐immune cell lineages including keratinocytes and endothelial cells. A better understanding of the multiple molecular mechanisms involved in the cellular action of FAEs will help to adapt and further improve the use of such small molecules for the treatment of psoriasis and other chronic inflammatory diseases. [ABSTRACT FROM AUTHOR]

Two sets of new ethyl 7-hydroxycoumarin-3-carboxylate derivatives were synthesized and characterized to study the liquid crystalline properties. Chemical structures were confirmed by IR, NMR, CHN analysis techniques. Mesomarphic properties were accomplished by DSC, POM and X-ray studies. Density functional theory calculations and photophysical studies also performed. In the first set, smaller homologues of alkoxybenzoic acid derivatives exhibit monotropic smectic A (SmA) and higher homologous exhibit enantiotropic smectic A mesophase. The second set alkyl biphenyl derivatives exhibit stable SmA and nematic (N) mesophases. The well defined focal conic texture for SmA and threaded texture for nematic mesophases have been observed. [ABSTRACT FROM AUTHOR]

A ruthenocenyl phosphino-oxazoline-ruthenium complex (RuPHOX−Ru) catalyzed asymmetric hydrogenation of α-aryl keto acids has been successfully developed, affording the corresponding chiral α-aryl α-hydroxy carboxylic acids in high yields and with up to 97% ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 5000 S/C) and the resulting products can be transformed to several chiral building blocks, biologically active compounds and chiral drugs. [ABSTRACT FROM AUTHOR]

Background: Hydroxy-carboxylic acid receptor 2 (HCA2, also called GPR109A) belongs to the G protein-coupled receptor (GPCR) family and is found in humans, rats, mice, hamsters and guinea pigs, but there are almost no reports of this protein in other species. In this investigation, we speculated that AMP010014A09 (AMP+) is a homologue of GPR109A in swine. Methods: To test this hypothesis, the following experiments were designed: monocytes isolated from the peripheral blood of swine were treated with LPS after pretreating with or without β-hydroxybutyric acid (BHBA), and the levels of pro-inflammatory cytokines and inflammatory proteins were assessed. cAMP levels induced by Forskolin in swine testicular (ST) and IPEC-J2 cells were detected with or without BHBA treatment and following silencing or stable transfection of the AMP+ gene. Results: AMP+ in swine exhibited a high level of homology with HM74A in humans and PUMA-G in mice. BHBA inhibited the LPS-induced secretion of the pro-inflammatory cytokines TNF-α, IL-6 and IL-1β and the inflammatory protein COX-2 in monocytes of swine. BHBA suppressed the Forskolin-induced cAMP level increase in ST cells, but failed to inhibit the accumulation of cAMP after the AMP+ gene was silenced with shRNA by transfecting cells with the pGPU6-GFP-Neo-AMP+-sus-392 plasmid. BHBA had no effect on cAMP levels in IPEC-J2 cells, but significantly inhibited the increase in cAMP induced by Forskolin treatment following transfection of the AMP+ gene into IPEC-J2 cells by a lentivirus vector. Conclusion: Our results indicated that AMP+ encodes a G proteincoupled receptor in Sus scrofa that inhibits cAMP levels and mediates anti-inflammatory effects in swine monocytes. [ABSTRACT FROM AUTHOR]

Interest in the equilibria and mechanisms of boron acid complexation reactions has increased dramatically in the past few years in part because of the effective use of boron acid complexation chemistry in saccharide recognition. In this study, it is shown that borate complex ions (1:1 − ) are capable of forming ternary mixed-ligand complexes (1:2 − ) with polyols over a wide range of pH thereby allowing the possible use of such 1:1 − borate complex ions in the recognition of saccharides. From a mechanistic perspective, it is also demonstrated that rate constants for the complexation reactions of borates with polyols correlate with the basicity of the borate anions. Therefore, depending on the specific boron acid, the pattern of reactivity with a particular ligand may be either RB(OH) 2 > RB(OH) 3 − or RB(OH) 3 − > RB(OH) 2 . [ABSTRACT FROM AUTHOR]

We describe herein a new strategy for the chemoselective synthesis of amides by using a metalcatalyzed hydroxy-directed reaction. A hydroxy group located at the β-position of an ester group promoted the activation of a carbonyl group with a tantalum alkoxide catalyst followed by amidation reactions, leading to a wide variety of β-hydroxyamides with excellent chemeselectivity. The chemoselective amidation strategy can be extended to the catalytic synthesis of dipeptide derivatives, which remains challenging research subjects in modern organic synthesis. [ABSTRACT FROM AUTHOR]

Oxidase-catalyzed kinetic resolution is important for the production of enantiopure 2-hydroxycarboxylic acids (2-HAs), which are versatile building blocks for the synthesis of many significant compounds. However, in contrast to that of ( R)-2-HAs, the production of ( S)-2-HA is challenging because of the lack of related oxidases. Herein, suitable enzymes were screened systematically through the analysis of numerous putative d-lactate oxidase sequences and identification of several required properties. Finally, a d-lactate oxidase from Gluconobacter oxydans 621H with advantageous characteristics, such as good solubility, broad substrate spectrum, and high stereoselectivity, was selected to resolve 2-HAs into ( S)-2-HAs. A variety of ( S)-2-HAs was produced successfully using this d-lactate oxidase with excellent enantiomeric excess values (>99 %). The presented screening criteria and approach for target biocatalysis suggested a guideline for the production of optically active chemicals such as ( S)-2-HAs. [ABSTRACT FROM AUTHOR]

The utility of the quadrupolar, spin 5/2 95 Mo nucleus in NMR studies of complexation of molybdate have been demonstrated using model alpha hydroxy carboxylic acids. The 95 Mo NMR spectra show a down field shift of the resonance upon complexation, presumably due to the smaller 1/Δ E paramagnetic shift term for the octahedral molybdate complexes relative to the tetrahedral molybdate ion. The 95 Mo resonances are sufficiently distinct to establish three solution complexes for the reaction of lactic acid with molybdate. The effect of the structure of hydroxy carboxylic acids on complexation to molybdate (MoO 4 2− ) was studied with 13 C and 95 Mo NMR spectroscopy. The use of the NMR spectra of both nuclei allows monitoring of the Lewis acidic molybdate site and the Lewis basic ligands. The beta hydroxy carboxylic acids, 3-hydroxypropanoic acid and salicylic acid, did not form complexes with molybdate, suggesting a preference for 5-membered chelated rings. The Lewis acidity of the negatively charged molybdate ion is rationalized with two schemes for the reaction with the chelating bidentate alpha hydroxy carboxylic acids. [ABSTRACT FROM AUTHOR]

The formation of pyridine carboxylic acids in interstellar ice grains was simulated by electron exposures of binary pyridine (C 5 H 5 N)-carbon dioxide (CO 2 ) ice mixtures at 10 K under contamination-free ultrahigh vacuum conditions. Chemical processing of the pristine ice and subsequent warm-up phase was monitored on line and in situ via Fourier transform infrared spectroscopy to probe for the formation of new radiation induced species. In the infrared spectra of the irradiated ice, bands assigned to nicotinic acid (niacin; vitamin B3; m -C 5 H 4 NCOOH) along with 2,3-, 2,5-, 3,4-, and 3,5-pyridine dicarboxylic acid (C 5 H 3 N(COOH) 2 ) were unambiguously identified along with the hydroxycarbonyl (HOCO) radical. Our study suggests that the reactive pathway responsible for pyridine carboxylic acids formation involves a HOCO intermediate, which forms through the reaction of suprathermal hydrogen ejected from pyridine with carbon dioxide. The newly formed pyridinyl radical may then undergo radical–radical recombination with a hydroxycarbonyl radical to form a pyridine carboxylic acid. [ABSTRACT FROM AUTHOR]

In batch fermentation of whey, selection of suitable species at desired conditions such as substrate, product concentrations, temperature and inoculum size were investigated. Four Lactobacillus species and one Lactococcus species were screened for lactic acid production. Among them L. bulgaricus ATCC 11842 were selected for further studies. The optimal growth of the selected organism for variable size of inocula was examined. The results indicated that inoculum size had insignificant effect on the cell and lactic acid concentration. The effect of temperature was also studied at 32, 37, 42 and 47°C. Results showed that the concentration of cell dry weight increased with increment of temperature from 32 to 42°C. The maximum cell and lactic acid concentration was obtained at 42°C. The effect of initial substrate concentration on lactic acid production was also examined. The optimum initial lactose concentration was found to be 90 g/l. [ABSTRACT FROM AUTHOR]

Not only short chain ω-hydroxycarboxylic acids, α,ω-dicarboxylic acids, and ω-aminocarboxylic acids but also medium to long chain carboxylic acids are widely used as building blocks and intermediates in the chemical, pharmaceutical, and food industries. Thereby, recent achievements in biological production of medium to long chain carboxylic acids are addressed here. ω-Hydroxycarboxylic and α,ω-dicarboxylic acids were synthesized via terminal C H bond oxygenation of fatty acids and/or internal oxidative cleavage of the fatty acid carbon skeletons. ω-Aminocarboxylic acids were enzymatically produced from ω-hydroxycarboxylic acids via ω-oxocarboxylic acids. Productivities and product yields of some of the products are getting close to the industrial requirements for large scale production. [ABSTRACT FROM AUTHOR]

A racemic N,N ′-dioxide-iron(III) complex was first found to be an efficient chemosensor for simultaneous determination of the absolute configuration, concentration, and enantiomeric excess (ee) of hydroxy carboxylic acids in aqueous solution via circular dichroism (CD) and fluorescence. The accuracy of the ee measurement is very good, within 3%. And the analysis is fast, eliminating laborious derivatization and elaborating purification steps. [ABSTRACT FROM AUTHOR]

Further studies of the direct enantioselective α-hydroxymethylation of aldehydes employing the α,α-diarylprolinol trimethylsilyl ether class of organocatalysis are described. This process has proven efficient for access to β-hydroxycarboxylic adds and δ-hydroxy-α,β-unsaturated esters from aldehydes in generally good yields, excellent enantioselectivity, and compatibility with a broad range of functional groups in the aldehyde. The goal of these studies was to identify the critical reaction variables that influence the yield and enantioselectrvrty of the α-hydroxymethylation process such as catalyst structure, pH of the medium, purity of the reactants and reagents particularly with respect to the presence of acidic impurities, and the nature of the buffer, along with the standard variables including solvent, time, temperature and mixing efficiency. The previously identified intermediate lactol has been further characterized and its reactivity examined. These studies have led to identification of the most critical variables translating directly into improved substrate scope, reprodudbility, enajitioselectivity, and yields. [ABSTRACT FROM AUTHOR]

RATIONALE: Characterising complex mixtures of organic compounds in polar fractions of heavy petroleum is challenging, but is important for pollution studies and for exploration and production geochemistry. Oil sands process-affected water (OSPW) stored in large tailings ponds by Canadian oil sands industries contains such mixtures. METHODS: A polar OSPW fraction was obtained by silver ion solid-phase extraction with methanol elution. This was examined by numerous methods, including electrospray ionisation (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) and ultra-high-pressure liquid chromatography (uHPLC)/Orbitrap MS, in multiple ionisation and MS/MS modes. Compounds were also synthesised for comparison. RESULTS: The major ESI ionisable compounds detected (+ion mode) were C15-28 SO3 species with 3-7 double bond equivalents (DBE) and C27-28 SO5 species with 5 DBE. ESI-MS/MS collision-induced losses were due to water, methanol, water plus methanol and water plus methyl formate, typical of methyl esters of hydroxy acids. Once the fraction was re-saponified, species originally detected by positive ion MS, could be detected only by negative ion MS, consistent with their assignment as sulphur-containing hydroxy carboxylic acids. The free acid of a keto dibenzothiophene alkanoic acid was added to an unesterified acid extract of OSPW in known concentrations as a putative internal standard, but attempted quantification in this way proved unreliable. CONCLUSIONS: The results suggest the more polar acidic organic SO3 constituents of OSPW include C15-28 S-containing, alicyclic and aromatic hydroxy carboxylic acids. SO5 species are possibly sulphone analogues of these. The origin of such compounds is probably via further biotransformation (hydroxylation) of the related S-containing carboxylic acids identified previously in a less polar OSPW fraction. The environmental risks, corrosivity and oil flow assurance effects should be easier to assess, given that partial structures are now known, although further identification is still needed. [ABSTRACT FROM AUTHOR]

A major problem of long-chain fatty acid (LCFA) hydroxylation using Escherichia coli is that FadD (long-chain fatty acyl-CoA synthetase), which is necessary for exogenous LCFA transport, also initiates cellular consumption of LCFA. In this study, an effective method to prevent the cellular consumption of LCFA without impairing its transport is proposed. The main idea is that a heterologous enzyme which consumes LCFA can replace FadD in LCFA transport. For the model heterologous enzyme, CYP153A from Marinobacter aquaeolei, which converts palmitic acid into ω-hydroxy palmitic acid, was expressed in E. coli. When fadD was deleted from an E. coli strain, CYP153A indeed maintained the ability to transport LCFA. A disadvantage of fadD deletion mutant is the fact that FadD deficiency downregulates the transcription of fadL (outer membrane LCFA transporter) via FadR (fatty acid metabolism regulator protein), was solved by fadL overexpression from a plasmid. In addition, the overexpression of fadL was able to offset catabolite repression on fadL, allowing glucose to be used as the primary carbon source. In conclusion, the strain with fadD deletion and fadL overexpression showed 5.5-fold increase in productivity compared to the wild-type strain, converting 2.6 g/L (10.0 mM) of palmitic acid into 2.4 g/L (8.8 mM) of ω-hydroxy palmitic acid in a shake flask. This simple genetic manipulation can be applied to any LCFA hydroxylation using E. coli. [ABSTRACT FROM AUTHOR]

Human pigmentation is a complex phenomenon commonly believed to serve a photoprotective function through the generation and strategic localization of black insoluble eumelanin biopolymers in sun exposed areas of the body. Despite compelling biomedical relevance to skin cancer and melanoma, eumelanin photoprotection is still an enigma: What makes this pigment so efficient in dissipating the excess energy brought by harmful UV-light as heat? Why has Nature selected 5,6-dihydroxyindole-2-carboxylic acid (DHICA) as the major building block of the pigment instead of the decarboxylated derivative (DHl)? By using pico- and femtosecond fluorescence spectroscopy we demonstrate herein that the excited state deactivation in DHICA oligomers is 3 orders of magnitude faster compared to DHI oligomers. This drastic effect is attributed to their specific structural patterns enabling multiple pathways of intra- and interunit proton transfer. The discovery that DHICA-based scaffolds specifically confer uniquely robust photoprotective properties to natural eumelanins settles a fundamental gap in the biology of human pigmentation and opens the doorway to attractive advances and applications. [ABSTRACT FROM AUTHOR]

An asymmetric hydrogenation of α-oxymethylcinnamic acids was developed by using chiral spiro phosphine-oxazoline/iridium complexes as catalysts to prepare β2-hydroxycarboxylic acids with high reactivity (TON up to 2000) and excellent enantioselectivity (up to 99.5% ee). By using this highly efficient asymmetric hydrogenation as a key step, a concise total synthesis of natural product homoisoflavone ( S)-(+)- 4 was accomplished. [ABSTRACT FROM AUTHOR]

An NAD-dependent D-lactate dehydrogenase (D-nLDH) of Lactobacillus bulgaricus ATCC 11842 was rationally re-designed for asymmetric reduction of a homologous series of α-keto carboxylic acids such as phenylpyruvic acid (PPA), α-ketobutyric acid, α-ketovaleric acid, β-hydroxypyruvate. Compared with wild-type D-nLDH, the Y52L mutant D-nLDH showed elevated activities toward unnatural substrates especially with large substitutes at C-3. By the biocatalysis combined with a formate dehydrogenase for in situ generation of NADH, the corresponding (R)-α-hydroxy carboxylic acids could be produced at high yields and highly optical purities. Taking the production of chiral (R)-phenyllactic acid (PLA) from PPA for example, 50 mMPPA was completely reduced to (R)-PLA in 90 min with a high yield of 99.0% and a highly optical purity (.99.9% e.e.) by the coupling system. The results presented in this work suggest a promising alternative for the production of chiral α-hydroxy carboxylic acids. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hydroxy acids and NaOH of black liquor were separated using SEC. [•] Co-operative sorption of NaOH enables using large injection volumes. [•] Separation mechanism was explained considering size-exclusion of individual ions. [Copyright &y& Elsevier]

For centuries mankind has stored its knowledge on paper, a remarkable biomaterial made of natural cellulose fibers. However, spontaneous cellulose degradation phenomena weaken and discolorate paper over time. The detailed knowledge of products arising from cellulose degradation is essential in understanding deterioration pathways and in improving durability of cultural heritage. In this study, for the first time, products of cellulose degradation were individually detected in solid paper samples by means of an extremely powerful proton HR-MAS NMR set-up, in combination to a wise use of both ancient and, as reference, artificially aged paper samples. Carboxylic acids, in addition to more complex dicarboxylic and hydroxy-carboxylic acids, were found in all samples studied. Since these products can catalyze further degradation, their knowledge is fundamental to improve conservation strategies of historical documents. Furthermore, the identification of compounds used in ancient production techniques, also suggests for artifacts dating, authentication and provenance. [ABSTRACT FROM AUTHOR]

Highlights: [•] In this work, the novel chiral derivatives of calix[4]arene were synthesized. [•] The chiral recognition properties of chiral calix[4]arenes were also investigated. [•] The receptors exhibited different chiral recognition abilities toward the enantiomers of guests. [•] NMR studies demonstrated that the receptors function as highly effective chiral shift reagents. [ABSTRACT FROM AUTHOR]

α-Hydroxy carboxylate ligands like gluconate or polyaminocarboxylate ligands such as ethylenediaminetetraacetate (EDTA) are frequently used in decontamination procedures at nuclear power plants. The presence of these organic substances among nuclear wastes could enhance the solubility of actinides by forming soluble complexes. Thermodynamic data on the stability of gluconate and EDTA with actinides are essential to predict their increase in mobility, especially in high pH systems characteristic of cement environments of a nuclear waste repository. In this work, the solubility of thorium oxyhydroxide in the presence of gluconate and EDTA has been studied. The results highlight the key role of these organics in increasing the solubility of thorium at pH = 12. The presence of calcium at concentrations below 10 mol·dm (characteristic of cement porewaters corresponding to cement compositions at the second degradation stage) does not seem to affect significantly the thorium solubility under the studied conditions. [ABSTRACT FROM AUTHOR]

Abstract: From our research of nonsecosteroidal vitamin D3 derivatives with gamma hydroxy carboxylic acid, we identified compound 6, with two CF3 groups in the side chain, as a most potent vitamin D receptor (VDR) agonist that shows superagonistic activity in VDRE reporter gene assay, MG-63 osteocalcin production assay and HL-60 cell differentiation assay. Compound 6 demonstrated that fluorination is as effective in the case of our nonsecosteroidal scaffold as in the case of secosteroidal VD3 analogs. X-ray analysis of the VDR with compound 6 revealed all of the six fluorine atoms of the hexafluoropropanol (HFP) moiety in the side chain effectively interacting with the VDR by both steric (van der Waals) and electrostatic (hydrogen bond, NH–F and CH–F) interactions. The HFP moiety of 6 effectively interacts with helix 12 (H12) of the VDR and stabilizes the position and the orientation of H12, which could result in stabilizing the coactivator and enhancing the VDR agonistic activity. [Copyright &y& Elsevier]

Interaction of actinides(IV) with hydroxyisobutyric acid (HHIB) in aqueous solutions and in the course of crystallization of solid compounds was studied. The complexes ML (M = U, Np, Pu; L is hydroxyisobutyrate anion; n = 1, 2, 3) exist in solution. Their apparent stepwise stability constants K′ were measured, and the overall concentration stability constants β of the complexes ML were calculated. For U(IV) and Np(IV), logβ is close to 13.3-13.4, and for Pu(IV), logβ = 14.5 ± 0.9 (ionic strength I = 0.1-0.3). In the course of crystallization in air, complexes of U(IV) with hydroxyisobutyric acid, as well as those with citric acid, undergo oxidative degradation, which can be accompanied by complete oxidation of U(IV). The crystalline compounds formed in the process are oxalates of U(IV) or U(VI). The complexation of Np(V) with HHIB was studied. NpO forms with HHIB the complexes NpOL and NpOL. Their concentration stability constants are log K = 2.04 ± 0.15 and log K = 0.71 ± 0.10 ( I = 0.4), i.e., logβ = 2.75 ± 0.25. [ABSTRACT FROM AUTHOR]

BACKGROUND AND PURPOSE 3-Hydroxy-octanoate, recently identified as a ligand for, the orphan GPCR, HCA3, is of particular interest given its ability to treat lipid disorders and atherosclerosis. Here we demonstrate the pathway of HCA3-mediated activation of ERK1/2. EXPERIMENTAL APPROACH Using CHO-K1 cells stably expressing HCA3 receptors and A431 cells, a human epidermoid cell line with high levels of endogenous expression of functional HCA3 receptors, HCA3-mediated activation of ERK1/2 was measured by Western blot. KEY RESULTS HCA3-mediated activation of ERK1/2 was rapid, peaking at 5 min, and was Pertussis toxin sensitive. Our data, obtained by time course analyses in combination with different kinase inhibitors, demonstrated that on agonist stimulation, HCA3 receptors evoked ERK1/2 activation via two distinct pathways, the PLC/PKC pathway at early time points (≤2 min) and the MMP/ epidermal growth factor receptor (EGFR) transactivation pathway with a maximum response at 5 min. Furthermore, our present results also indicated that the βγ-subunits of the Gi protein play a critical role in HCA3-activated ERK1/2 phosphorylation, whereas β-arrestins and Src were not required for ERK1/2 activation. CONCLUSIONS AND IMPLICATIONS We have described the molecular mechanisms underlying the coupling of human HCA3 receptors to the ERK1/2 MAP kinase pathway in CHO-K1 and A431 cells, which implicate the Gi protein-initiated, PLC/PKC- and platelet-derived growth factor receptor/EGFR transactivation-dependent pathways. These observations may provide new insights into the pharmacological effects and the physiological functions modulated by the HCA3-mediated activation of ERK1/2. [ABSTRACT FROM AUTHOR]

The O-3-pyrroline-1-carbonyl (O-Pyroc) group and 3-pyrrolinamide are useful removable protecting groups for the kinetic resolution of racemic α-hydroxycarboxylic acids, β-hydroxy�carboxylic acids, 1,2-dicarboxylic acids, and 1,2-diols using the l-histidine-derived bifunctional catalysts. The Pyroc group can be easily introduced from Pyroc chloride. Selective deprotection of the Pyroc group and 3-pyrrolinamide can be carried out via DDQ oxidation followed by hydrolysis using sodium hydroxide, without epimerization. [ABSTRACT FROM AUTHOR]

Abstract: Quantum chemical calculations were performed on six amino acids and six hydroxy carboxylic acids. Possible correlations between experimentally obtained inhibition efficiencies (ΔE) for pitting corrosion of Al 7075 alloy in NaCl solution and parameters such as electronic charges on active centres (qO, qN), dipole moment (μ), highest occupied (E H) and lowest unoccupied (E L) molecular orbital energies and the differences between them (E L−E H), HOMO–LUMO gap were investigated. Possible inhibition mechanism for pitting corrosion of Al 7075 in NaCl solution was proposed from the obtained relations between quantum chemical parameters computed using AM1 and PM3 methods and experimentally obtained inhibition efficiencies. [Copyright &y& Elsevier]

Abstract: Carbohydrate-rich biomass residues, i.e. sugar beet molasses, whey powder, wine yeast, potato peel sludge, spent hops, malt dust and apple marc, were tested as starting materials for the generation of marketable chemicals, e.g. aliphatic acids, sugar acids and mono-/disaccharides. Residues were oxidized or hydrolyzed under acidic or alkaline conditions applying conventional laboratory digestion methods and microwave assisted techniques. Yields and compositions of the oxidation products differed according to the oxidizing agent used. Main products of oxidation by 30% HNO3 were acetic, glucaric, oxalic and glycolic acids. Applying H2O2/CuO in alkaline solution, the organic acid yields were remarkably lower with formic, acetic and threonic acids as main products. Gluconic acid was formed instead of glucaric acid throughout. Reaction of a 10% H2O2 solution with sugar beet molasses generated formic and lactic acids mainly. Na2S2O8 solutions were very inefficient at oxidizing the residues. Glucose, arabinose and galactose were formed during acidic hydrolysis of malt dust and apple marc. The glucose content reached 0.35g per gram of residue. Important advantages of the microwave application were lower reaction times and reduced reagent demands. [Copyright &y& Elsevier]

The catalytic wet oxidation: (WO) of four low molecular weight sodium salts of hydroxy carboxylic acids that can be found in alumina industry process water has been investigated using a representative synthetic solution. The most active catalyst: (CuO) catalysed the WO of the compounds studied predominantly via a homogenous complexation based reaction mechanism. [ABSTRACT FROM AUTHOR]

A gradient programmed reversed phase high-performance liquid chromatographic (RP-HPLC) method is described for the quantitative determination of some aldehydes, hydroxy aldehydes, unsaturated aldehydes, hydroxy carboxylic acids, carboxylic acids, alcohols and polyols using an ultraviolet and a refractive index detector in series. The sample matrices are synthesis mixtures of hydroxy carboxylic acids. The structures of the hydroxy aldehyde intermediates are determined by13C NMR and the influence of sample preparation on analysis results is discussed. The limits of detection and the precision of the method are evaluated. [ABSTRACT FROM AUTHOR]

The reaction of Np(VI) with organic acid anions in solutions containing lithium salts of tartaric, malic, α-aminoglutaric, and trihydroxyglutaric acids was studied. Changes in the solution spectra show that Np(VI) forms complexes with organic acid anions, which is followed by the reduction of Np(VI) to Np(V). Similar processes occur in solutions containing Pu(VI) and sodium phenylglycolate or ammonium salicylate. In weakly acidic solutions, the loss of the Np(VI) and Pu(VI) concentrations is a linear function of time. The possible mechanism of the redox reactions was suggested. [ABSTRACT FROM AUTHOR]

The article discusses the dithiophosphorylation of chemical compound methyl (S)-(—)-lactate. Topics mentioned include the asymmetric carbon atom of hydroxy carboxylic acids which are accessible chiral synthons, the capacity of lactic acid to inhibit the putrefactive bacteria, and the use of lactate for treatment of anemia.

Review: 85 refs. [ABSTRACT FROM AUTHOR]

An efficient and improved procedure is developed for the title synthesis. [ABSTRACT FROM AUTHOR]

Review: 128 refs. [ABSTRACT FROM AUTHOR]