Articoli di riviste: "Carboxylic acids Metabolism"

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Iwami, Y., S. Hata, N. Takahashi e T. Yamada. "Difference in Amounts between Titratable Acid and Total Carboxylic Acids Produced by Oral Streptococci during Sugar Metabolism". Journal of Dental Research 68, n. 1 (gennaio 1989): 16–19. http://dx.doi.org/10.1177/00220345890680010101.

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The acid produced by the resting cells of Streptococcus mutans NCTC 10449 and HS 6 and S. sanguis ATCC 10556 during sugar metabolism was estimated with a pH-stat and a carboxylic acid analyzer. Lactic, formic, acetic, pyruvic, and carbonic acids were detected in the reaction mixtures, but propionic, citric, succinic, iso-butyric, butyric, iso-valeric, and valeric acids were not detected. The amount of titratable acid estimated by alkaline titration with the pH-stat was larger than the amount of total carboxylic acids estimated with the carboxylic acid analyzer. The difference in quantity between the titratable and the total carboxylic acids increased significantly with an increase in the period of incubation with sugar. Moreover, the value of the alkaline titration of standard lactic, formic, acetic, and pyruvic acids was equal to the amount analyzed with the carboxylic acid analyzer. The results indicated that these two streptococci produced not only these carboxylic acids but also other acid(s), possibly non-carboxylic acid(s), during their sugar metabolism.

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Goyal, R., R. Tardif e J. Brodeur. "Influence of a cysteine prodrug, L-2-oxothiazolidine-4-carboxylic acid, on the urinary elimination of mercapturic acids of ethylene oxide, dibromoethane, and acrylonitrile: a dose–effect study". Canadian Journal of Physiology and Pharmacology 67, n. 3 (1 marzo 1989): 207–12. http://dx.doi.org/10.1139/y89-035.

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Metabolic disposition of ethylene oxide, dibromoethane, and acrylonitrile in rats after acute exposure was studied by examining the relationship between dose and urinary metabolites, and by establishing the influence of a glutathione precursor, L-2-oxothiazolidine-4-carboxylic acid (OTCA), on the above relationship. Respective urinary metabolites, hydroxyethylmercapturic acid, cyanoethylmercapturic acid, thiocyanate, and ethylene glycol, were quantified to estimate the extent to which each compound was metabolized. The animals were given either ethylene oxide (0.34, 0.68, or 1.36 mmol/kg), dibromoethane (0.2, 0.4, or 0.6 mmol/kg), or acrylonitrile (0.10, 0.38, or 0.76 mmol/kg). Urine samples were collected at 24 h. The metabolic biotransformation of all three chemicals to their respective mercapturic acids was strongly indicative of saturable metabolism. Administration of OTCA (4–5 mmol/kg) enhanced gluthathione availability and increased excretion of urinary mercapturic acids at the higher doses of the chemicals. This study indicates that OTCA increases the capacity for detoxification via the glutathione pathway thereby partially correcting the nonlinearity between the administered dose of ethylene oxide, dibromoethane, and acrylonitrile and the amount of certain urinary metabolites.Key words: ethylene oxide metabolism, dibromoethane metabolism, acrylonitrile metabolism, mercapturic acids, glutathione, cysteine prodrugs, L-2-oxothiazolidine-4-carboxylic acid.

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Sarkar, Omprakash, A. Naresh Kumar, Shikha Dahiya, K. Vamshi Krishna, Dileep Kumar Yeruva e S. Venkata Mohan. "Regulation of acidogenic metabolism towards enhanced short chain fatty acid biosynthesis from waste: metagenomic profiling". RSC Advances 6, n. 22 (2016): 18641–53. http://dx.doi.org/10.1039/c5ra24254a.

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Darnell, Malin, e Lars Weidolf. "Metabolism of Xenobiotic Carboxylic Acids: Focus on Coenzyme A Conjugation, Reactivity, and Interference with Lipid Metabolism". Chemical Research in Toxicology 26, n. 8 (5 luglio 2013): 1139–55. http://dx.doi.org/10.1021/tx400183y.

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5

Beaulieu, Pierre L., René Coulombe, James Gillard, Christian Brochu, Jianmin Duan, Michel Garneau, Eric Jolicoeur et al. "Allosteric N-acetamide-indole-6-carboxylic acid thumb pocket 1 inhibitors of hepatitis C virus NS5B polymerase — Acylsulfonamides and acylsulfamides as carboxylic acid replacements". Canadian Journal of Chemistry 91, n. 1 (gennaio 2013): 66–81. http://dx.doi.org/10.1139/cjc-2012-0319.

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Acylsulfonamide and acylsulfamide as surrogates for the carboxylic acid function of N-acetamide-indole-6-carboxylic acids were evaluated as allosteric inhibitors of hepatitis C virus (HCV) NS5B polymerase. Several analogs displayed excellent antiviral potency against both 1a and 1b HCV genotypes in cell-based subgenomic replicon assays. Structure–activity relationships (SAR) are discussed in the context of the crystal structure of an inhibitor − NS5B polymerase complex. Absorption, distribution, metabolism, and excretion pharmacokinetic (ADME-PK) properties of this class of inhibitors are also described.

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Omran, Arthur, Cesar Menor-Salvan, Greg Springsteen e Matthew Pasek. "The Messy Alkaline Formose Reaction and Its Link to Metabolism". Life 10, n. 8 (28 luglio 2020): 125. http://dx.doi.org/10.3390/life10080125.

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Sugars are essential for the formation of genetic elements such as RNA and as an energy/food source. Thus, the formose reaction, which autocatalytically generates a multitude of sugars from formaldehyde, has been viewed as a potentially important prebiotic source of biomolecules at the origins of life. When analyzing our formose solutions we find that many of the chemical species are simple carboxylic acids, including α-hydroxy acids, associated with metabolism. In this work we posit that the study of the formose reaction, under alkaline conditions and moderate hydrothermal temperatures, should not be solely focused on sugars for genetic materials, but should focus on the origins of metabolism (via metabolic molecules) as well.

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Knights, Kathleen M., Matthew J. Sykes e John O. Miners. "Amino acid conjugation: contribution to the metabolism and toxicity of xenobiotic carboxylic acids". Expert Opinion on Drug Metabolism & Toxicology 3, n. 2 (aprile 2007): 159–68. http://dx.doi.org/10.1517/17425255.3.2.159.

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Bock, Susanne, Ulrich A. Sedlmeier e Klaus H. Hoffmann. "Metabolism of absorbed short-chain carboxylic acids by the freshwater oligochaete Tubifex tubifex". Comparative Biochemistry and Physiology Part B: Comparative Biochemistry 92, n. 1 (gennaio 1989): 35–40. http://dx.doi.org/10.1016/0305-0491(89)90309-x.

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Knights, Kathleen M. "ROLE OF HEPATIC FATTY ACID:COENZYME A LIGASES IN THE METABOLISM OF XENOBIOTIC CARBOXYLIC ACIDS". Clinical and Experimental Pharmacology and Physiology 25, n. 10 (ottobre 1998): 776–82. http://dx.doi.org/10.1111/j.1440-1681.1998.tb02152.x.

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Arun, Viswanath, Takashi Mino e Tomonori Matsuo. "Metabolism of Carboxylic Acids Located in and around the Glycolytic Pathway and the TCA Cycle in the Biological Phosphorus Removal Process". Water Science and Technology 21, n. 4-5 (1 aprile 1989): 363–74. http://dx.doi.org/10.2166/wst.1989.0238.

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Anaerobic batch experiments were performed to measure the profile of various parameters when phosphorus accumulating sludge acclimatized under anaerobic-aerobic operation is fed with malic, lactic, pyruvic, propionic and succinic acids - carboxylic acids that lie in the vicinity of the Glycolytic pathway and the Tricarboxylic acid cycle - two pathways central to the utilization of organics as sources of energy and carbon in most microorganisms. Carbon dioxide gas produced during substrate uptake was also measured. In most cases, intra-cellular carbohydrate reserves are consumed and the NADH2 that is consequently produced requires that there be some subsequent reaction that utilizes it.

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Di Carlo, Frederick J. "Structure-Activity Relationships (Sar) and Structure-Metabolism Relationships (Smr) Affecting the Teratogenicity of Carboxylic Acids". Drug Metabolism Reviews 22, n. 5 (gennaio 1990): 411–49. http://dx.doi.org/10.3109/03602539008991446.

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12

Daneshvar, Maryam I., John B. Brooks, Georgia B. Malcolm e Leo Pine. "Analyses of fermentation products of Listeria species by frequency-pulsed electron-capture gas–liquid chromatography". Canadian Journal of Microbiology 35, n. 8 (1 agosto 1989): 786–93. http://dx.doi.org/10.1139/m89-131.

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Aerobic fermentation broths of eight Listeria monocytogenes strains, two or more strains of the remaining six Listeria species, and one strain of Jonesia denitrificans were examined by frequency-pulsed electron-capture gas–liquid chromatography for carboxylic acids, alcohols, amines, and hydroxy acids. All species produced acetic, isobutyric, butyric, isovaleric, phenylacetic, lactic, 2-hydroxybutyric, 2-hydroxyvaleric, and 2-hydroxyisocaproic acids. Propionic acid was not formed, and traces of isocaproic acid were observed. Of the alcohol and amine derivatives observed, only acetylmethylcarbinol, butylamine, and putrecine were identified. Recognition of the products of glucose and amino acid metabolism serves to further characterize the members of the genus Listeria both taxonomically and physiologically.Key words: Listeria, growth products, frequency-pulsed electron-capture gas–liquid chromatography.

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13

Leitão, Ana Lúcia, e Francisco J. Enguita. "Structural Insights into Carboxylic Polyester-Degrading Enzymes and Their Functional Depolymerizing Neighbors". International Journal of Molecular Sciences 22, n. 5 (26 febbraio 2021): 2332. http://dx.doi.org/10.3390/ijms22052332.

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Esters are organic compounds widely represented in cellular structures and metabolism, originated by the condensation of organic acids and alcohols. Esterification reactions are also used by chemical industries for the production of synthetic plastic polymers. Polyester plastics are an increasing source of environmental pollution due to their intrinsic stability and limited recycling efforts. Bioremediation of polyesters based on the use of specific microbial enzymes is an interesting alternative to the current methods for the valorization of used plastics. Microbial esterases are promising catalysts for the biodegradation of polyesters that can be engineered to improve their biochemical properties. In this work, we analyzed the structure-activity relationships in microbial esterases, with special focus on the recently described plastic-degrading enzymes isolated from marine microorganisms and their structural homologs. Our analysis, based on structure-alignment, molecular docking, coevolution of amino acids and surface electrostatics determined the specific characteristics of some polyester hydrolases that could be related with their efficiency in the degradation of aromatic polyesters, such as phthalates.

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Van Dyk, Tina K., Lori J. Templeton, Keith A. Cantera, Pamela L. Sharpe e F. Sima Sariaslani. "Characterization of the Escherichia coli AaeAB Efflux Pump: a Metabolic Relief Valve?" Journal of Bacteriology 186, n. 21 (1 novembre 2004): 7196–204. http://dx.doi.org/10.1128/jb.186.21.7196-7204.2004.

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ABSTRACT Treatment of Escherichia coli with p-hydroxybenzoic acid (pHBA) resulted in upregulation of yhcP, encoding a protein of the putative efflux protein family. Also upregulated were the adjacent genes yhcQ, encoding a protein of the membrane fusion protein family, and yhcR, encoding a small protein without a known or suggested function. The function of the upstream, divergently transcribed gene yhcS, encoding a regulatory protein of the LysR family, in regulating expression of yhcRQP was shown. Furthermore, it was demonstrated that several aromatic carboxylic acid compounds serve as inducers of yhcRQP expression. The efflux function encoded by yhcP was proven by the hypersensitivity to pHBA of a yhcP mutant strain. A yhcS mutant strain was also hypersensitive to pHBA. Expression of yhcQ and yhcP was necessary and sufficient for suppression of the pHBA hypersensitivity of the yhcS mutant. Only a few aromatic carboxylic acids of hundreds of diverse compounds tested were defined as substrates of the YhcQP efflux pump. Thus, we propose renaming yhcS, yhcR, yhcQ, and yhcP, to reflect their role in aromatic carboxylic acid efflux, to aaeR, aaeX, aaeA, and aaeB, respectively. The role of pHBA in normal E. coli metabolism and the highly regulated expression of the AaeAB efflux system suggests that the physiological role may be as a “metabolic relief valve” to alleviate toxic effects of imbalanced metabolism.

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15

She, Jianqing, Manyun Guo, Hongbing Li, Junhui Liu, Xiao Liang, Peining Liu, Bo Zhou et al. "Targeting amino acids metabolic profile to identify novel metabolic characteristics in atrial fibrillation". Clinical Science 132, n. 19 (5 ottobre 2018): 2135–46. http://dx.doi.org/10.1042/cs20180247.

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Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia whose incidence is on the rise globally. However, the pathophysiologic mechanism of AF remains poorly understood and there has been a lack of circulatory markers to diagnose and predict prognosis of AF. In the present study, by measuring metabolic profile and analyzing plasma amino acid levels in AF patients, we sought to determine whether amino acid metabolism was correlated to the occurrence of AF. Methods: Consecutive patients admitted to hospital for AF were enrolled. Plasma samples were obtained after overnight fast and a profile of 61 amino acids was then measured using gas chromatography/mass spectrometry (GC/MS). Results: Twenty-three AF and thirty-seven control patients were enrolled in the study. A number of plasma amino acids were altered in AF, which showed significant prediction value for AF. Intriguingly, circulating 4-hydroxypyrrolidine-2-carboxylic was gradually lowered with the persistence of AF. Plasma amino acid levels were more strongly correlated with each other in AF as compared with control. Conclusion: By utilizing non-target metabolic profile surveys, we have found a number of altered amino acids, which exhibit diagnostic value for AF. Enhanced amino acids correlation network further identified AF as a metabolism disorder.

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Covington, D. K., C. A. Briscoe, A. J. Brown e C. K. Jayawickreme. "The G-protein-coupled receptor 40 family (GPR40–GPR43) and its role in nutrient sensing". Biochemical Society Transactions 34, n. 5 (1 ottobre 2006): 770–73. http://dx.doi.org/10.1042/bst0340770.

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Recent deorphanization efforts have paired the G-protein-coupled receptors GPR40, GPR41 and GPR43 with fatty acids as endogenous ligands. While carboxylic acids have been historically known to serve as fuel sources and biomarkers of disease, these studies demonstrate that fatty acids can act as signalling molecules at the cell-surface level. This receptor subfamily shares approx. 30% identity among members, with some limited cross-over between ligand activities. Generalized expression patterns within the pancreatic β-cell, adipose depots and the gastrointestinal tract infer involvement in energy source recognition, absorption, storage and/or metabolism. GPR40, activated by medium and long-chain fatty acids, has been shown to potentiate insulin secretion at the β-cell, and has been hypothesized to participate in the detrimental effects of chronic fatty acid exposure on β-cell function. GPR41 and GPR43 have been reported to stimulate leptin release and adipogenesis respectively via activation by short-chain fatty acids. These common themes implicate GPR40, GPR41 and GPR43 in playing significant roles in metabolic diseases, such as diabetes, obesity and the metabolic syndrome.

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Floret, Fabienne, Lal C. Chaudhary, William C. Ellis, Suliman El Hassan, Nest McKain, C. James Newbold e R. John Wallace. "Influence of 1-[(E)-2-(2-Methyl-4-Nitrophenyl)Diaz-1-enyl]Pyrrolidine-2-Carboxylic Acid and Diphenyliodonium Chloride on Ruminal Protein Metabolism and Ruminal Microorganisms". Applied and Environmental Microbiology 65, n. 7 (1 luglio 1999): 3258–60. http://dx.doi.org/10.1128/aem.65.7.3258-3260.1999.

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ABSTRACT The effects of 1-[(E)-2-(2-methyl-4-nitrophenyl)diaz-1-enyl]pyrrolidine-2-carboxylic acid (LY29) and diphenyliodonium chloride (DIC) on the degradation of protein to ammonia were determined in a mixed rumen microbial population taken from sheep on a grass hay-concentrate diet. Both compounds decreased NH3 production by inhibiting deamination of amino acids. LY29, but not DIC, inhibited growth of the high-activity ammonia-producing species, Clostridium aminophilum and Clostridium sticklandii.

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Komuro, Masakatsu, Tsunehiko Higuchi e Masaaki Hirobe. "Application of chemical cytochrome P-450 model systems to studies on drug metabolism—VIII. Novel metabolism of carboxylic acids via oxidative decarboxylation". Bioorganic & Medicinal Chemistry 3, n. 1 (gennaio 1995): 55–65. http://dx.doi.org/10.1016/0968-0896(94)00141-o.

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Wojakowska, Anna, Monika Pietrowska, Piotr Widlak, Dariusz Dobrowolski, Edward Wylęgała e Dorota Tarnawska. "Metabolomic Signature Discriminates Normal Human Cornea from Keratoconus—A Pilot GC/MS Study". Molecules 25, n. 12 (25 giugno 2020): 2933. http://dx.doi.org/10.3390/molecules25122933.

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The molecular etiology of keratoconus (KC), a pathological condition of the human cornea, remains unclear. The aim of this work was to perform profiling of metabolites and identification of features discriminating this pathology from the normal cornea. The combination of gas chromatography and mass spectrometry (GC/MS) techniques has been applied for profiling and identification of metabolites in corneal buttons from 6 healthy controls and 7 KC patients. An untargeted GC/MS-based approach allowed the detection of 377 compounds, including 46 identified unique metabolites, whose levels enabled the separation of compared groups of samples in unsupervised hierarchical cluster analysis. There were 13 identified metabolites whose levels differentiated between groups of samples. Downregulation of several carboxylic acids, fatty acids, and steroids was observed in KC when compared to the normal cornea. Metabolic pathways associated with compounds that discriminated both groups were involved in energy production, lipid metabolism, and amino acid metabolism. An observed signature may reflect cellular processes involved in the development of KC pathology, including oxidative stress and inflammation.

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Ruprecht, J. J., e E. R. S. Kunji. "Structural Mechanism of Transport of Mitochondrial Carriers". Annual Review of Biochemistry 90, n. 1 (20 giugno 2021): 535–58. http://dx.doi.org/10.1146/annurev-biochem-072820-020508.

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Members of the mitochondrial carrier family [solute carrier family 25 (SLC25)] transport nucleotides, amino acids, carboxylic acids, fatty acids, inorganic ions, and vitamins across the mitochondrial inner membrane. They are important for many cellular processes, such as oxidative phosphorylation of lipids and sugars, amino acid metabolism, macromolecular synthesis, ion homeostasis, cellular regulation, and differentiation. Here, we describe the functional elements of the transport mechanism of mitochondrial carriers, consisting of one central substrate-binding site and two gates with salt-bridge networks on either side of the carrier. Binding of the substrate during import causes three gate elements to rotate inward, forming the cytoplasmic network and closing access to the substrate-binding site from the intermembrane space. Simultaneously, three core elements rock outward, disrupting the matrix network and opening the substrate-binding site to the matrix side of the membrane. During export, substrate binding triggers conformational changes involving the same elements but operating in reverse.

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López-Millán, Ana Flor, Fermín Morales, Yolanda Gogorcena, Anunciación Abadía e Javier Abadía. "Iron resupply-mediated deactivation of Fe-deficiency stress responses in roots of sugar beet". Functional Plant Biology 28, n. 3 (2001): 171. http://dx.doi.org/10.1071/pp00105.

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Different root zones with or without increased Fe-reducing activities have been studied in Fe-deficient sugar beet (Beta vulgaris L.) plants after Fe resupply to the nutrient solution. The subapical regions of roots from Fe-deficient plants decreased by 19 and 88% their capacity to reduce ferric chelates after 24 and 96 h of Fe resupply, respectively. Iron resupply caused 52 and 96% decreases in phosphoenolpyruvate carboxylase activity in root extracts after 24 and 96 h, respectively, and also caused general decreases in other enzyme activities involved in carboxylic acid metabolism. The large pools of carboxylic acids in Fe-deficient roots decreased by 9 and 48% after 24 and 96 h of Fe resupply, respectively. The activities of pyruvate decarboxylase and lactate dehydrogenase, enzymes related to anaerobic metabolism, decreased by 88% after 24 h of Fe resupply. The mitochondrial quinone and pyridine nucleotide pools became more oxidised in the Fe-deficient root tips after Fe resupply. Iron resupply caused a 70% decrease in root oxygen consumption rates 96 h after Fe resupply. Results indicate that deactivation of the Fe deficiency stress responses of sugar beet roots upon Fe resupply occurs in a progressive manner in a time scale of several days.

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Lewis, Dustin F., Rory L. Roten, Wesley J. Everman, Travis W. Gannon, Robert J. Richardson e Fred H. Yelverton. "Absorption, Translocation, and Metabolism of Aminocyclopyrachlor in Tall Fescue (Lolium arundinaceum)". Weed Science 61, n. 3 (settembre 2013): 348–52. http://dx.doi.org/10.1614/ws-d-12-00189.1.

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Synthetic auxin herbicides are commonly used in forage, pasture, range, and turfgrass settings for dicotyledonous weed control. Aminocyclopyrachlor (AMCP) is a newly developed pyrimidine carboxylic acid with a chemical structure and mode of action similar to the pyridine carboxylic acids—aminopyralid, clopyralid, and picloram. Injury to sensitive dicotyledonous plants has been observed following exposure to monocotyledonous plant material previously treated with pyridine compounds. The absorption, translocation, and metabolism of AMCP has been documented in susceptible broadleaf weeds; however, no information is available, to our knowledge, regarding AMCP fate in tolerant Poaceae, which may serve as the vector for off-target plant injury. Based on this premise, research was conducted to characterize absorption, translocation, and metabolism of AMCP in tall fescue.14C-AMCP was applied to single tiller tall fescue plant foliage under controlled laboratory conditions at North Carolina State University (Raleigh, NC). Radiation was quantified in leaf wash, treated leaf, foliage, crown, roots, and root exudates at 3, 12, 24, 48, 96, and 192 h after treatment (HAT).14C-AMCP was rapidly absorbed by tall fescue, reaching 38 and 68% at 3 and 48 HAT, respectively. Translocation of14C-AMCP was limited to the foliage, which reached maximum translocation (34%) at 96 HAT. Most of the recovered14C-AMCP remained in the leaf wash, treated leaf, or foliage, whereas minimal radiation was detected in the crown, roots, or root exudates throughout the 192-h period. No AMCP metabolism was observed in tall fescue through the 192 HAT. These data suggest AMCP applied to tall fescue can remain bioavailable, and mishandling treated plant material could result in off-target injury.

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Syromolotov, Alexander V., Alexander A. Kimyashov e Sergey V. Sukhorukov. "Decarboxylation 2'-dicarboxy-5-(methyl-5'-indolyl-3')- indolyl-3-acetic acid with use of salts of copper". Butlerov Communications 58, n. 4 (30 aprile 2019): 58–61. http://dx.doi.org/10.37952/roi-jbc-01/19-58-4-58.

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In this article a decarboxylation method based on the use of quinoline with a copper salt is discussed. Decarboxylation is the elimination of CO2 from the carboxylic group of carboxylic acids or the carboxylate group of their salts. The process is used to produce a large number of organic compounds, such classes as alkanes, alkenes, alcohols, ketones, ethers and esters. Decarboxylation plays an important role in the metabolism of living organisms, namely in the decarboxylation of amino acids. From this we can conclude that the process is important to study. Decarboxylation proceeds in different ways. The most common methods of decarboxylation includes heating in various conditions. For example, such as heating in the presence of acids and alkalis, under severe conditions with quinoline, thermal oxidation in the presence of transition metal salts, Kolbe reaction. In the procces of the CO2 removal group in relation to amino acids there are several types: α-decarboxylation, decarboxylation, associated with the trans-amination reaction and the condensation reaction of molecules. In the synthesis of substituted auxin 2'-dicarboxy-5-(methyl-5'indolyl-3')-indolyl-3-acetic acid, the yield of the product was not high. The usual heating in the presence of alkali output was less than 5%, and in this work it was decided to use other methods of decarboxylation to increase the yield of the product. The aim of the work is to improve the method of decarboxylation of carboxyindolyl substrates for increasing product yield and to compare with the result obtained by ordinary heating of this substances in the presence of alkali. At the end of the work summed up. Found the optimal conditions for the process of decarboxylation of investigated substrates. Optimal conditions chosen based on product yield. To confirm the chemical structures of the substances, 1H NMR, IR spectroscopy, and elemental analysis were used.

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Merelli, B., S. Hamm, A. Carlin-Sinclair e J. C. Cherton. "N-acylaziridines as potential proinsecticides of carboxylic acids☆Part VI. Direct HPLC monitoring of the metabolism in insect tissues". Journal of Chromatography B 826, n. 1-2 (5 novembre 2005): 129–38. http://dx.doi.org/10.1016/j.jchromb.2005.07.037.

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O'Kane, Robyn L., e Richard A. Hawkins. "Na+-dependent transport of large neutral amino acids occurs at the abluminal membrane of the blood-brain barrier". American Journal of Physiology-Endocrinology and Metabolism 285, n. 6 (dicembre 2003): E1167—E1173. http://dx.doi.org/10.1152/ajpendo.00193.2003.

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Several Na+-dependent carriers of amino acids exist on the abluminal membrane of the blood-brain barrier (BBB). These Na+-dependent carriers are in a position to transfer amino acids from the extracellular fluid of brain to the endothelial cells and thence to the circulation. To date, carriers have been found that may remove nonessential, nitrogen-rich, or acidic (excitatory) amino acids, all of which may be detrimental to brain function. We describe here Na+-dependent transport of large neutral amino acids across the abluminal membrane of the BBB that cannot be ascribed to currently known systems. Fresh brains, from cows killed for food, were used. Microvessels were isolated, and contaminating fragments of basement membranes, astrocyte fragments, and pericytes were removed. Abluminal-enriched membrane fractions from these microvessels were prepared. Transport was Na+dependent, voltage sensitive, and inhibited by 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid, a particular inhibitor of the facilitative large neutral amino acid transporter 1 (LAT1) system. The carrier has a high affinity for leucine ( Km21 ± 7 μM) and is inhibited by other neutral amino acids, including glutamine, histidine, methionine, phenylalanine, serine, threonine, tryptophan, and tyrosine. Other established neutral amino acids may enter the brain by way of LAT1-type facilitative transport. The presence of a Na+-dependent carrier on the abluminal membrane capable of removing large neutral amino acids, most of which are essential, from brain indicates a more complex situation that has implications for the control of essential amino acid content of brain.

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Curiao, Tânia, Emmanuela Marchi, Carlo Viti, Marco R. Oggioni, Fernando Baquero, José Luis Martinez e Teresa M. Coque. "Polymorphic Variation in Susceptibility and Metabolism of Triclosan-Resistant Mutants of Escherichia coli and Klebsiella pneumoniae Clinical Strains Obtained after Exposure to Biocides and Antibiotics". Antimicrobial Agents and Chemotherapy 59, n. 6 (30 marzo 2015): 3413–23. http://dx.doi.org/10.1128/aac.00187-15.

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Abstract (sommario):

ABSTRACTExposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selectedEscherichia coliandKlebsiella pneumoniaemutants.E. coliandK. pneumoniaemutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chloride (BKC), chlorhexidine (CHX) or sodium hypochlorite (SHC), and ampicillin or ciprofloxacin. Alterations in antimicrobial susceptibility and metabolism in mutants were tested using Phenotype MicroArrays. The expression of AcrAB pump and global regulators (SoxR, MarA, and RamA) was measured by quantitative reverse transcription-PCR (qRT-PCR), and the central part of thefabIgene was sequenced. The fitness costs of resistance were assessed by a comparison of relative growth rates. Triclosan-resistant (TRIr) and triclosan-hypersusceptible (TRIhs) mutants ofE. coliandK. pneumoniaewere obtained after selection with biocides and/or antibiotics.E. coliTRIrmutants, including those with mutations in thefabIgene or in the expression ofacrB,acrF, andmarA, exhibited changes in susceptibility to TRI, CHX, and antibiotics. TRIrmutants for which the TRI MIC was high presented improved metabolism of carboxylic acids, amino acids, and carbohydrates. In TRIrmutants, resistance to one antimicrobial provoked hypersusceptibility to another one(s). TRIrmutants had fitness costs, particularlymarA-overexpressing (E. coli) orramA-overexpressing (K. pneumoniae) mutants. TRI, BKC, and CIP exposure frequently yielded TRIrmutants exhibiting alterations in AraC-like global regulators (MarA, SoxR, and RamA), AcrAB-TolC, and/or FabI, and influencing antimicrobial susceptibility, fitness, and metabolism. These various phenotypes suggest a trade-off of different selective processes shaping the evolution toward antibiotic/biocide resistance and influencing other adaptive traits.

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Zarafu, Irina, Lilia Matei, Coralia Bleotu, Petre Ionita, Arnaud Tatibouët, Anca Păun, Ioana Nicolau et al. "Synthesis, Characterization, and Biologic Activity of New Acyl Hydrazides and 1,3,4-Oxadiazole Derivatives". Molecules 25, n. 14 (21 luglio 2020): 3308. http://dx.doi.org/10.3390/molecules25143308.

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Starting from isoniazid and carboxylic acids as precursors, thirteen new hydrazides and 1,3,4-oxadiazoles of 2-(4-substituted-phenoxymethyl)-benzoic acids were synthesized and characterized by appropriate means. Their biological properties were evaluated in terms of apoptosis, cell cycle blocking, and drug metabolism gene expression on HCT-8 and HT-29 cell lines. In vitro antimicrobial tests were performed by the microplate Alamar Blue assay for the anti-mycobacterial activities and an adapted agar disk diffusion technique for other non-tubercular bacterial strains. The best antibacterial activity (anti-Mycobacterium tuberculosis effects) was proved by 9. Compounds 7, 8, and 9 determined blocking of G1 phase. Compound 7 proved to be toxic, inducing apoptosis in 54% of cells after 72 h, an effect that can be predicted by the increased expression of mRNA caspases 3 and 7 after 24 h. The influence of compounds on gene expression of enzymes implicated in drug metabolism indicates that synthesized compounds could be metabolized via other pathways than NAT2, spanning adverse effects of isoniazid. Compound 9 had the best antibacterial activity, being used as a disinfectant agent. Compounds 7, 8, and 9, seemed to have antitumor potential. Further studies on the action mechanism of these compounds on the cell cycle may bring new information regarding their biological activity.

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28

Jackson, Dennis P., Douglas A. Gray, Vincent L. Morris e Diane A. Cuppels. "Identification of a DNA region required for growth of Pseudomonas syringae pv. tomato on tomato plants". Canadian Journal of Microbiology 38, n. 9 (1 settembre 1992): 883–90. http://dx.doi.org/10.1139/m92-144.

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Abstract (sommario):

The prototrophic Pseudomonas syringae pv. tomato mutant DC3481, which is the result of a single-site Tn5 insertion, cannot grow and cause disease on tomato plants and cannot use the major organic acids of tomato, i.e., citric, malic, succinic, and tartaric acids, as sole carbon sources. Although nonpathogenic, strain DC3481 can still induce a hypersensitive reaction in nonhost plants. We have identified a 30-kb fragment of P. syringae pv. tomato wild-type DNA that can complement this mutant. EcoRI fragments from this region were subcloned and individually subjected to functional complementation analysis. The 3.8-kb fragment, which was the site of the Tn5 insertion, restored pathogenicity and the ability to use all the major organic acids of tomato as carbon sources. It shares sequence homology with several P. syringae pathovars but not other bacterial tomato pathogens. Our results indicate that sequences on the 3.8-kb EcoRI fragment are required for both the ability to grow on tomato leaves (and thus cause disease) and the utilization of carboxylic acids common to tomato. The 3.8-kb fragment may contain a sequence (or sequences) that regulates both traits. Key words: Pseudomonas syringae pv. tomato, phytopathogenicity, Tn5, tricarboxylic acid metabolism, bacterial speck, growth in planta.

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29

Ramos-González, Marı́a-Isabel, Patricia Godoy, Miguel Alaminos, Arie Ben-Bassat e Juan-Luis Ramos. "Physiological Characterization ofPseudomonas putida DOT-T1E Tolerance top-Hydroxybenzoate". Applied and Environmental Microbiology 67, n. 9 (1 settembre 2001): 4338–41. http://dx.doi.org/10.1128/aem.67.9.4338-4341.2001.

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ABSTRACT Pseudomonas putida DOT-T1E was isolated as a toluene-tolerant strain. We show that it is also able to grow on high concentrations (up to 17 g/liter [123 mM]) ofp-hydroxybenzoate (4HBA). Tolerance to this aromatic carboxylic acid (up to 30 g/liter [217 mM]) is improved by preexposing the cells to low 4HBA concentrations; the adaptation process is caused by the substrate itself rather than by products resulting from its metabolism. The mechanisms of 4HBA tolerance seem to involve increased rigidity of the cell membrane as a result of a decrease in the cis/trans ratio of unsaturated fatty acids. In addition, energy-dependent efflux systems seem to operate in the exclusion of 4HBA from the cell membranes.

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30

Lhuguenot, J. C., A. C. Macherey e M. Paitry. "Quantitative structure-activity relationship (QSAR) for peroxisome proliferation induced by branched carboxylic acids issued from diester plasticizers metabolism in rats". Toxicology Letters 95 (luglio 1998): 87. http://dx.doi.org/10.1016/s0378-4274(98)80345-7.

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31

Chatzigianni, Martina, Konstantinos A. Aliferis, Georgia Ntatsi e Dimitrios Savvas. "Effect of N Supply Level and N Source Ratio on Cichorium spinosum L. Metabolism". Agronomy 10, n. 7 (2 luglio 2020): 952. http://dx.doi.org/10.3390/agronomy10070952.

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Abstract (sommario):

Cichorium spinosum L. is considered a health-promoting vegetable that has been recently introduced in cultivation, and thus information on the responses of its different ecotypes to N supply level and source is largely fragmented. To cover this gap of knowledge, seeds of two different local ecotypes of C. spinosum L. originating from a coastal and a montane habitat of the island of Crete were propagated, and the obtained seedlings were grown hydroponically. The supplied nutrient solution differed in the total-N level (4 or 16 mmol L−1) and N source (NH4-N/-N/total-N: 0.05, 0.25, or 0.50). The impact of N supply level and N source ratio on the metabolism of the two ecotypes was assessed by gas chromatography–electron impact–mass spectrometry (GC/EI/MS) metabolomics combined with bioinformatics analyses. A general disturbance of the plants’ metabolism was recorded, with results revealing that the genotypic composition was the predominant factor for the observed discriminations. The montane ecotype exhibited substantially lower levels of metabolites such as fructose and α-α-trehalose, and higher levels of glucose, myo-inositol, and fatty acids compared to the coastal ecotype when both were treated with low N. Carboxylic acids and metabolites of the tricarboxylic acid cycle (TCA) were also substantially affected by the N supply level and the NH4-N/total-N ratio. The obtained information could be further exploited in the breeding of cultivars with improved nutritional value and resilience to variations in N supply levels and sources.

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32

Chovanec, Peter, Michal Kaliňák, Tibor Liptaj, Naďa Pronayová, Tibor Jakubík, Daniela Hudecová e Ľudovít Varečka. "Study ofTrichoderma viridemetabolism under conditions of the restriction of oxidative processes". Canadian Journal of Microbiology 51, n. 10 (1 settembre 2005): 853–62. http://dx.doi.org/10.1139/w05-075.

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Abstract (sommario):

Trichoderma viride was capable of growth and conidiation in the presence of high concentrations of the uncoupler 3,3′,4′,5-tetrachlorosalicylanilide (up to 100 µmol·L–1) and of the respiration inhibitor mucidin (up to 100 µmol·L–1) in both submerged and surface cultivation. When vegetative mycelia were cultivated on the solid Czapek-Dox medium with yeast autolysate under an anaerobic and CO2-containing atmosphere, the growth was observed only rarely but the microorganism survived as long as 3 months under these conditions. Major products of metabolism of both aerobic and anaerobic submerged mycelia were identified by means of1H-NMR measurements. Major products excreted to the medium under aerobic conditions were succinic and citric acids. Major metabolites present in the submerged mycelia were γ-aminobutyric (and glutamic) acid and alanine. Under anaerobic conditions, citric acid was not excreted into the medium but ethanol appeared. Its production could not be increased upon increasing the sugar concentration. The appearance of secondary metabolites was found to be modified by oxygen availability during the mycelial growth. Results suggest that the vegetative form of T. viride is capable of fermentative metabolism characterized by the production of ethanol and succinate and that the excretion of carboxylic acids is developmentally regulated and modified by oxygen availability.Key words: Trichoderma, mycelia, anaerobiosis, citrate, succinate, ethanol, GABA.

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33

Schühle, Karola, e Georg Fuchs. "Phenylphosphate Carboxylase: a New C-C Lyase Involved in Anaerobic Phenol Metabolism in Thauera aromatica". Journal of Bacteriology 186, n. 14 (15 luglio 2004): 4556–67. http://dx.doi.org/10.1128/jb.186.14.4556-4567.2004.

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Abstract (sommario):

ABSTRACT The anaerobic metabolism of phenol in the beta-proteobacterium Thauera aromatica proceeds via carboxylation to 4-hydroxybenzoate and is initiated by the ATP-dependent conversion of phenol to phenylphosphate. The subsequent para carboxylation of phenylphosphate to 4-hydroxybenzoate is catalyzed by phenylphosphate carboxylase, which was purified and studied. This enzyme consists of four proteins with molecular masses of 54, 53, 18, and 10 kDa, whose genes are located adjacent to each other in the phenol gene cluster which codes for phenol-induced proteins. Three of the subunits (54, 53, and 10 kDa) were sufficient to catalyze the exchange of 14CO2 and the carboxyl group of 4-hydroxybenzoate but not phenylphosphate carboxylation. Phenylphosphate carboxylation was restored when the 18-kDa subunit was added. The following reaction model is proposed. The 14CO2 exchange reaction catalyzed by the three subunits of the core enzyme requires the fully reversible release of CO2 from 4-hydroxybenzoate with formation of a tightly enzyme-bound phenolate intermediate. Carboxylation of phenylphosphate requires in addition the 18-kDa subunit, which is thought to form the same enzyme-bound energized phenolate intermediate from phenylphosphate with virtually irreversible release of phosphate. The 54- and 53-kDa subunits show similarity to UbiD of Escherichia coli, which catalyzes the decarboxylation of a 4-hydroxybenzoate derivative in ubiquinone (ubi) biosynthesis. They also show similarity to components of various decarboxylases acting on aromatic carboxylic acids, such as 4-hydroxybenzoate or vanillate, whereas the 10-kDa subunit is unique. The 18-kDa subunit belongs to a hydratase/phosphatase protein family. Phenylphosphate carboxylase is a member of a new family of carboxylases/decarboxylases that act on phenolic compounds, use CO2 as a substrate, do not contain biotin or thiamine diphosphate, require K+ and a divalent metal cation (Mg2+or Mn2+) for activity, and are strongly inhibited by oxygen.

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34

Gaudêncio, Fabrício Nascimento, Vinícius Menezes Tunholi-Alves, Mariana Gomes Lima, Patrícia Silva Gôlo, Isabele da Costa Angelo, Rosane Nora Castro, Adivaldo Henrique da Fonseca, Fabio Barbour Scott e Jairo Pinheiro. "Alterations in the oxidative metabolism of Rhipicephalus (Boophilus) microplus ticks in response to exposure to the insect growth regulator fluazuron". Revista Brasileira de Parasitologia Veterinária 25, n. 1 (11 marzo 2016): 54–60. http://dx.doi.org/10.1590/s1984-29612016006.

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Abstract Aiming to characterize the potential off-target effects of fluazuron on ticks, biochemical analyses were conducted to evaluate changes in the carbohydrate metabolism of Rhipicephalus (Boophilus) microplus ticks after exposure to fluazuron. Hemolymph and fat body were collected from female ticks before and after (4, 8 and 15 days) exposure to fluazuron. Spectrophotometric analyses were done to quantify glucose concentration and lactate dehydrogenase (LDH) activity in the hemolymph and the concentration of glycogen in the tick’s fat body. High Performance Liquid Chromatography (HPLC) was employed to determine the concentration of carboxylic acids in the hemolymph and to evaluate changes in intermediary metabolic processes requiring oxygen consumption. Increases in the levels of LDH activity and lactic acid concentration indicated that fluazuron enhanced fermentative metabolism in ticks. Exposure to fluazuron was also found to increase glucose concentrations in the hemolymph over time, although no significant differences were noted daily. In addition to expanding the body of knowledge about the mode of action of fluazuron, investigations into these mechanisms may also be useful in discovering new and as yet unexplored secondary effects.

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35

Morton, Allyson M., Jeremy D. Furtado, Jane Lee, William Amerine, Michael H. Davidson e Frank M. Sacks. "The effect of omega-3 carboxylic acids on apolipoprotein CIII−containing lipoproteins in severe hypertriglyceridemia". Journal of Clinical Lipidology 10, n. 6 (novembre 2016): 1442–51. http://dx.doi.org/10.1016/j.jacl.2016.09.005.

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36

Varynskyi, B. О. "Optimization of detection range of hydrazides of carboxylic acids and 2-acylhydrazinсarbothioamids by HPLC-ECI-MC". Farmatsevtychnyi zhurnal, n. 4 (4 settembre 2018): 59–64. http://dx.doi.org/10.32352/0367-3057.4.15.02.

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Abstract (sommario):

Elaboration of control steps of hydrazids and сarbothioamids, raw materials in the synthesis of 1,2,4-triazol-3-yl-thioacetate acids, potential drug substances on research and production stage is an important task. The study of adsorption, distribution, metabolism and excretion of these substances has great importance. The HPLC-MS is the most universal and selective method used in these cases. The aim of our study was to determine the optimal conditions for mass spectrometric detection of ionization in electrospray in HPLC-MS іzonіcotinohydrazide, furan-2-carbohydrazide, 2-morpholinoacetohydrazide, 2-methoxybenzohydrazide, 2-isonicotinoyl-N-(2-methoxyphenyl)hydrazine-1-carbothioamide, 2-(furan-2-carbonyl)-N-phenylhydrazine-1-carbothioamide, 2-(2-morpholinoacetyl)-N-phenylhydrazine-1-carbothioamide, N-methyl-2-(2-morpholinoacetyl)hydrazine-1-carbothioamide, 2-(2-methoxybenzoyl)hydrazine-1-carbothioamide, precursor substances in the synthesis of salts of 1,2,4-triazol-3-yl-thioacetate acids for 8 synthetic schemes using full factorial design on 3 factors and polynomial regression equations. Work was carried out using flow injection analysis (the technique of direct sample introduction into the ion source) on a liquid chromatograph Agilent 1260 Infinity HPLC System with a single quadrupole mass spectrometer Agilent 6120. The optimal conditions of mass spectrometric detection series hydrazides and сarbothioamides for HPLC-ESI-MS on the basis of the calculated maxima polynomial regression functions were obtained. The equation of polynomial regression for the corresponding hydrazides and carbatioamides were suggested. The equations show the dependence of the mass detector signal intensity on three important factors: dryng gas temperature, the fragmentor voltage, the nebulizer pressure. The optimal conditions of mass spectrometric detection choice to maximize the signal detector and thus increase the sensitivity and selectivity of the determinations. It may allow partially separate the signal of these substances from the impurities signal because these conditions have specificity.

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37

Ribot, Joan, Andrea Arreguín, Ondrej Kuda, Jan Kopecky, Andreu Palou e Maria Luisa Bonet. "Novel Markers of the Metabolic Impact of Exogenous Retinoic Acid with A Focus on Acylcarnitines and Amino Acids". International Journal of Molecular Sciences 20, n. 15 (25 luglio 2019): 3640. http://dx.doi.org/10.3390/ijms20153640.

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Abstract (sommario):

Treatment with all-trans retinoic acid (ATRA), the carboxylic form of vitamin A, lowers body weight in rodents by promoting oxidative metabolism in multiple tissues including white and brown adipose tissues. We aimed to identify novel markers of the metabolic impact of ATRA through targeted blood metabolomics analyses, with a focus on acylcarnitines and amino acids. Blood was obtained from mice treated with a high ATRA dose (50 mg/kg body weight/day, subcutaneous injection) or placebo (controls) during the 4 days preceding collection. LC-MS/MS analyses with a focus on acylcarnitines and amino acids were conducted on plasma and PBMC. Main results showed that, relative to controls, ATRA-treated mice had in plasma: increased levels of carnitine, acetylcarnitine, and longer acylcarnitine species; decreased levels of citrulline, and increased global arginine bioavailability ratio for nitric oxide synthesis; increased levels of creatine, taurine and docosahexaenoic acid; and a decreased n-6/n-3 polyunsaturated fatty acids ratio. While some of these features likely reflect the stimulation of lipid mobilization and oxidation promoted by ATRA treatment systemically, other may also play a causal role underlying ATRA actions. The results connect ATRA to specific nutrition-modulated biochemical pathways, and suggest novel mechanisms of action of vitamin A-derived retinoic acid on metabolic health.

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38

Paiva, Sandra, Dita Strachotová, Helena Kučerová, Otakar Hlaváček, Sandra Mota, Margarida Casal, Zdena Palková e Libuše Váchová. "The transport of carboxylic acids and important role of the Jen1p transporter during the development of yeast colonies". Biochemical Journal 454, n. 3 (29 agosto 2013): 551–58. http://dx.doi.org/10.1042/bj20120312.

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Abstract (sommario):

On solid substrates, yeast colonies pass through distinct developmental phases characterized by the changes in pH of their surroundings from acidic to nearly alkaline and vice versa. At the beginning of the alkali phase colonies start to produce ammonia, which functions as a quorum-sensing molecule inducing the reprogramming of cell metabolism. Such reprogramming includes, among others, the activation of several plasma membrane transporters and is connected with colony differentiation. In the present study, we show that colony cells can use two transport mechanisms to import lactic acid: a ‘saturable’ component of the transport, which requires the presence of a functional Jen1p transporter, and a ‘non-saturable’ component (diffusion) that is independent of Jen1p. During colony development, the efficiency of both transport components changes similarly in central and outer colonial cells. Although the lactate uptake capacity of central cells gradually decreases during colony development, the lactate uptake capacity of outer cells peaks during the alkali phase and is also kept relatively high in the second acidic phase. This lactate uptake profile correlates with the localization of the Jen1p transporter to the plasma membrane of colony cells. Both lactic acid uptake mechanisms are diminished in sok2 colonies where JEN1 expression is decreased. The Sok2p transcription factor may therefore be involved in the regulation of non-saturable lactic acid uptake in yeast colonies.

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39

De Bruin, Tjerk, Hong Yang, Mats Kvarnström, Torbjörn Lundström e Michael Davidson. "Omega-3 Carboxylic Acids In Severe Hypertriglyceridemia With Triglycerides Greater Than 885mg/Dl (>10mmol/L)". Journal of Clinical Lipidology 10, n. 3 (maggio 2016): 702. http://dx.doi.org/10.1016/j.jacl.2016.03.077.

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40

Wu, Qikui, Xue Zhao, Chen Chen, Zihan Zhang e Fangyuan Yu. "Metabolite Profiling and Classification of Developing Styrax tonkinensis Kernels". Metabolites 10, n. 1 (1 gennaio 2020): 21. http://dx.doi.org/10.3390/metabo10010021.

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Abstract (sommario):

Background: Styrax tonkinensis is an economic tree species with high timber, medicine, oil, and ornamental value. Its seed, containing a particularly high oil content, are widely studied for their biodiesel properties by nutritional components and oil body ultrastructure. However, their comprehensive biochemical compositions have not been studied. Methods: During S. tonkinensis kernel development, we collected samples from four time points for metabolite profiling and classification through gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. Results: A total of 187 and 1556 metabolites were obtained, respectively. All of the metabolites were grouped into 19 and 21 classes by their chemical properties and into 8 clusters based on their change trends, respectively. Among all the metabolites, carboxylic acids and derivatives, flavonoids, fatty acyls, glycerophospholipids, organooxygen compounds, prenol lipids, and steroids and steroid derivatives were the main components. Alanine, glutamine, tryptophan, tyrosine and valine were the five most abundant amino acids. Palmitic acid, stearic acid, oleic acid and linoleic acid were the four major free fatty acids. Flavans, flavonoid glycosides and o-methylated flavonoids were the three major flavonoids. The differential metabolites distributions between different time points were identified. A pathway enrichment was performed, which was mainly focused on three groups, amino acids metabolism, carbon flow from sucrose to lipid and secondary metabolites biosynthesis. Conclusions: It’s the first time to analyze the metabolite fingerprinting for developing S. tonkinensis kernels and identify varied kinds of flavonoids. We performed metabolite profiling, classification and pathway enrichment to assess the comprehensive biochemical compositions. Our results described the change in major metabolites and main metabolic processes during S. tonkinensis kernel development and provided a variety of bases for seed applications as biofuel or medicine.

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41

Klyachenko, O. L., e A. F. Likhanov. "Content of Triterpene saponins and phenolics compounds in leaves of in vitro Beta vulgaris L. genotypes". Ukrainian Journal of Ecology 7, n. 4 (28 dicembre 2017): 564–68. http://dx.doi.org/10.15421/2017_161.

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Abstract (sommario):

<p>An important element in plants adaptation to adverse environmental stress factors is the synthesis of secondary metabolites which involved in formation for the constitutional stability of plant organism. Saponins play an important role in the regulation of metabolic processes and the development of adaptive and defense plant reactions. Triterpene saponins have pronounced surface-active properties, increase activity of certain enzymes and perform antioxidant function, which in general determines their important role in formation of a common nonspecific plant resistance system. Sugar beet contains saponins of the triterpenoid type. Our experiments were shown that some vegetative parts of in vitro plants of sugar beet accumulate secondary metabolites including phenolic carboxylic acids, flavonoids and saponins, which play an important role in the formation for the constitutional resistance. The general condition of the plant organism and the survival strategy depends on activity of phenolic substances and saponins synthesis. Phenolic carboxylic acids in leaves of in vitro sugar beet plants were determined by thin layer chromatography method. Generally, in leaves of sugar beet varieties, hybrids were found saponins with Rf values of 0.21, 0.32, 0.35, and 0.51. Qualitative composition and quantitative indices of triterpene saponins and phenolic compounds content in sugar beet leaves during in vitro cultivation have sortspecific character, due to the peculiarities of their metabolism. Taking into account the absolutely identical composition of nutrient medium, same photo- and thermo-regimes for cultivation of in vitro sugar beet, triterpenoid saponins with Rf = 0,56 and 0,62 are biochemical markers which determine adaptive potential of plants-regenerants. This makes it possible to consider it expedient carrying out the researches of content of triterpene saponins as a marker for primary diagnostics and selection of plants-regenerants with a high adaptive potential and drought resistance at the initial stages of selection.</p>

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42

Peters, Franziska, Michael Rother e Matthias Boll. "Selenocysteine-Containing Proteins in Anaerobic Benzoate Metabolism of Desulfococcus multivorans". Journal of Bacteriology 186, n. 7 (1 aprile 2004): 2156–63. http://dx.doi.org/10.1128/jb.186.7.2156-2163.2004.

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Abstract (sommario):

ABSTRACT The sulfate-reducing bacterium Desulfococcus multivorans uses various aromatic compounds as sources of cell carbon and energy. In this work, we studied the initial steps in the aromatic metabolism of this strictly anaerobic model organism. An ATP-dependent benzoate coenzyme A (CoA) ligase (AMP plus PPi forming) composed of a single 59-kDa subunit was purified from extracts of cells grown on benzoate. Specific activity was highest with benzoate and some benzoate derivatives, whereas aliphatic carboxylic acids were virtually unconverted. The N-terminal amino acid sequence showed high similarities with benzoate CoA ligases from Thauera aromatica and Azoarcus evansii. When cultivated on benzoate, cells strictly required selenium and molybdenum, whereas growth on nonaromatic compounds, such as cyclohexanecarboxylate or lactate, did not depend on the presence of the two trace elements. The growth rate on benzoate was half maximal with 1 nM selenite present in the growth medium. In molybdenum- and/or selenium-depleted cultures, growth on benzoate could be induced by addition of the missing trace elements. In extracts of cells grown on benzoate in the presence of [75Se]selenite, three radioactively labeled proteins with molecular masses of ∼100, 30, and 27 kDa were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The 100- and 30-kDa selenoproteins were 5- to 10-fold induced in cells grown on benzoate compared to cells grown on lactate. These results suggest that the dearomatization process in D. multivorans is not catalyzed by the ATP-dependent Fe-S enzyme benzoyl-CoA reductase as in facultative anaerobes but rather involves unknown molybdenum- and selenocysteine-containing proteins.

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43

Kuzina, Vera, e Enrique Cerdá-Olmedo. "Modification of Sexual Development and Carotene Production by Acetate and Other Small Carboxylic Acids in Blakeslea trispora and Phycomyces blakesleeanus". Applied and Environmental Microbiology 72, n. 7 (luglio 2006): 4917–22. http://dx.doi.org/10.1128/aem.02845-05.

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Abstract (sommario):

ABSTRACT In Phycomyces blakesleeanus and Blakeslea trispora (order Mucorales, class Zygomycetes), sexual interaction on solid substrates leads to zygospore development and to increased carotene production (sexual carotenogenesis). Addition of small quantities of acetate, propionate, lactate, or leucine to mated cultures on minimal medium stimulated zygospore production and inhibited sexual carotenogenesis in both Phycomyces and Blakeslea. In Blakeslea, the threshold acetate concentration was <1 mmol/liter for both effects, and the concentrations that had one-half of the maximal effect were <2 mmol/liter for carotenogenesis and >7 mmol/liter for zygosporogenesis. The effects on Phycomyces were similar, but the concentrations of acetate had to be multiplied by ca. 3 to obtain the same results. Inhibition of sexual carotenogenesis by acetate occurred normally in Phycomyces mutants that cannot use acetate as a carbon source and in mutants whose dormant spores cannot be activated by acetate. Small carboxylic acids may be signals that, independent of their ability to trigger spore germination in Phycomyces, modify metabolism and development during the sexual cycle of Phycomyces and Blakeslea, uncoupling two processes that were thought to be linked and mediated by a common mechanism.

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Pretorius, Chanel J., Fidele Tugizimana, Paul A. Steenkamp, Lizelle A. Piater e Ian A. Dubery. "Metabolomics for Biomarker Discovery: Key Signatory Metabolic Profiles for the Identification and Discrimination of Oat Cultivars". Metabolites 11, n. 3 (12 marzo 2021): 165. http://dx.doi.org/10.3390/metabo11030165.

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Abstract (sommario):

The first step in crop introduction—or breeding programmes—requires cultivar identification and characterisation. Rapid identification methods would therefore greatly improve registration, breeding, seed, trade and inspection processes. Metabolomics has proven to be indispensable in interrogating cellular biochemistry and phenotyping. Furthermore, metabolic fingerprints are chemical maps that can provide detailed insights into the molecular composition of a biological system under consideration. Here, metabolomics was applied to unravel differential metabolic profiles of various oat (Avena sativa) cultivars (Magnifico, Dunnart, Pallinup, Overberg and SWK001) and to identify signatory biomarkers for cultivar identification. The respective cultivars were grown under controlled conditions up to the 3-week maturity stage, and leaves and roots were harvested for each cultivar. Metabolites were extracted using 80% methanol, and extracts were analysed on an ultra-high performance liquid chromatography (UHPLC) system coupled to a quadrupole time-of-flight (qTOF) high-definition mass spectrometer analytical platform. The generated data were processed and analysed using multivariate statistical methods. Principal component analysis (PCA) models were computed for both leaf and root data, with PCA score plots indicating cultivar-related clustering of the samples and pointing to underlying differential metabolic profiles of these cultivars. Further multivariate analyses were performed to profile differential signatory markers, which included carboxylic acids, amino acids, fatty acids, phenolic compounds (hydroxycinnamic and hydroxybenzoic acids, and associated derivatives) and flavonoids, among the respective cultivars. Based on the key signatory metabolic markers, the cultivars were successfully distinguished from one another in profiles derived from both leaves and roots. The study demonstrates that metabolomics can be used as a rapid phenotyping tool for cultivar differentiation.

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Wu, Miao, Ming Zhang, Wei Ding, Lin Lan, Zhilin Liu, Lingzhan Miao e Jun Hou. "Microbial Carbon Metabolic Functions in Sediments Influenced by Resuspension Event". Water 13, n. 1 (23 dicembre 2020): 7. http://dx.doi.org/10.3390/w13010007.

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Microorganisms in sediments are an important part of the aquatic ecosystem, and their functional activities are sensitive to external environmental pressure. Shallow lakes are characterized by frequent sediment resuspension events, leading to large amounts of nutrients being released. However, information about the potential impacts of sediment resuspension events on the functional activities of microbial communities is limited. In this study, the responses of microbial carbon metabolism in sediments under different wind–wave disturbance were analyzed by BIOLOG ECO microplates. The results showed that under four disturbance conditions (wind speeds of 0, 1.60, 3.62, and 14.10 m/s), the total carbon metabolism function of the sediment microbial community (represented as average well-color development, AWCD) remained unchanged (p > 0.05), and the final total AWCD value stabilized at about 1.70. However, compared with the control group, some specific carbon sources (e.g., amines and carboxylic acids) showed significant changes (p < 0.05). We found that short-term (8 h) resuspension events did not affect the total carbon metabolism of sediment microbial communities, while it affected the microbial utilization ability of some specific types of carbon sources. For example, we found that the microbial utilization capacity of polymers in the 14.10 m/s group was the best. This study provides a new insight into the carbon cycle process of shallow lake sediments that resuspension events will affect the carbon cycle process of sediments.

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Reithuber, Elisabeth, Priyanka Nannapaneni, Olena Rzhepishevska, Anders E. G. Lindgren, Oleksandr Ilchenko, Staffan Normark, Fredrik Almqvist, Birgitta Henriques-Normark e Peter Mellroth. "The Bactericidal Fatty Acid Mimetic 2CCA-1 Selectively Targets Pneumococcal Extracellular Polyunsaturated Fatty Acid Metabolism". mBio 11, n. 6 (15 dicembre 2020): e03027-20. http://dx.doi.org/10.1128/mbio.03027-20.

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ABSTRACTStreptococcus pneumoniae, a major cause of pneumonia, sepsis, and meningitis worldwide, has the nasopharynges of small children as its main ecological niche. Depletion of pneumococci from this niche would reduce the disease burden and could be achieved using small molecules with narrow-spectrum antibacterial activity. We identified the alkylated dicyclohexyl carboxylic acid 2CCA-1 as a potent inducer of autolysin-mediated lysis of S. pneumoniae, while having low activity against Staphylococcus aureus. 2CCA-1-resistant strains were found to have inactivating mutations in fakB3, known to be required for uptake of host polyunsaturated fatty acids, as well as through inactivation of the transcriptional regulator gene fabT, vital for endogenous, de novo fatty acid synthesis regulation. Structure activity relationship exploration revealed that, besides the central dicyclohexyl group, the fatty acid-like structural features of 2CCA-1 were essential for its activity. The lysis-inducing activity of 2CCA-1 was considerably more potent than that of free fatty acids and required growing bacteria, suggesting that 2CCA-1 needs to be metabolized to exert its antimicrobial activity. Total lipid analysis of 2CCA-1 treated bacteria identified unique masses that were modeled to 2CCA-1 containing lysophosphatidic and phosphatidic acid in wild-type but not in fakB3 mutant bacteria. This suggests that 2CCA-1 is metabolized as a fatty acid via FakB3 and utilized as a phospholipid building block, leading to accumulation of toxic phospholipid species. Analysis of FabT-mediated fakB3 expression elucidates how the pneumococcus could ensure membrane homeostasis and concurrent economic use of host-derived fatty acids.IMPORTANCE Fatty acid biosynthesis is an attractive antibiotic target, as it affects the supply of membrane phospholipid building blocks. In Streptococcus pneumoniae, it is not sufficient to target only the endogenous fatty acid synthesis machinery, as uptake of host fatty acids may bypass this inhibition. Here, we describe a small-molecule compound, 2CCA-1, with potent bactericidal activity that upon interactions with the fatty acid binding protein FakB3, which is present in a limited number of Gram-positive species, becomes metabolized and incorporated as a toxic phospholipid species. Resistance to 2CCA-1 developed specifically in fakB3 and the regulatory gene fabT. These mutants reveal a regulatory connection between the extracellular polyunsaturated fatty acid metabolism and endogenous fatty acid synthesis in S. pneumoniae, which could ensure balance between efficient scavenging of host polyunsaturated fatty acids and membrane homeostasis. The data might be useful in the identification of narrow-spectrum treatment strategies to selectively target members of the Lactobacillales such as S. pneumoniae.

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Sener, A., F. Malaisse-Lagae, C. G. Östenson e W. J. Malaisse. "Metabolism of endogenous nutrients in islets of Goto-Kakizaki (GK) rats". Biochemical Journal 296, n. 2 (1 dicembre 1993): 329–34. http://dx.doi.org/10.1042/bj2960329.

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The metabolism of endogenous nutrients was examined in pancreatic islets of control and Goto-Kakizaki (GK) rats. At the ultrastructural level, no glycogen was found in the islet cells of GK rats, a situation similar to that prevailing in normal islets. Likewise, by measuring the output of L-lactate from islets first incubated at 16.7 mM D-glucose and then at 2.8 mM D-glucose, no evidence of glycogenolysis was found in the islets of GK rats. The production of NH4+ and that of 14CO2 from islets prelabelled with either L-[U-14C]glutamine or [U-14C]palmitate were higher, however, in GK than in control rats. The changes in NH4+ and 14CO2 production evoked by D-glucose, by a non-metabolized analogue of L-leucine (2-amino-bicyclo[2,2,1]heptane-2-carboxylic acid; BCH) and by 3-phenylpyruvate were qualitatively comparable in control and GK rats. The secretory response to these three secretagogues was severely decreased in the islets of GK rats. This coincided with an impaired enhancing action of D-glucose on the conversion of [2-3H]glycerol into 3HOH. It is concluded that the catabolism of endogenous amino and fatty acids in islets is greater in GK than in control rats, especially at low D-glucose concentration. This may account, in part at least, for the altered secretory response to BCH and 3-phenylpyruvate. For glucose-induced insulin release, however, an impaired acceleration of the glycerol phosphate shuttle apparently also participates in the secretory defect.

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Gimeno, Isabel, Pablo García-Manrique, Susana Carrocera, Cristina López-Hidalgo, Luis Valledor, David Martín-González e Enrique Gómez. "The Metabolic Signature of In Vitro Produced Bovine Embryos Helps Predict Pregnancy and Birth after Embryo Transfer". Metabolites 11, n. 8 (27 luglio 2021): 484. http://dx.doi.org/10.3390/metabo11080484.

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In vitro produced (IVP) embryos show large metabolic variability induced by breed, culture conditions, embryonic stage and sex and gamete donors. We hypothesized that the birth potential could be accurately predicted by UHPLC-MS/MS in culture medium (CM) with the discrimination of factors inducing metabolic variation. Day-6 embryos were developed in single CM (modified synthetic oviduct fluid) for 24 h and transferred to recipients as fresh (28 ETs) or frozen/thawed (58 ETs) Day-7 blastocysts. Variability was induced with seven bulls, slaughterhouse oocyte donors, culture conditions (serum + Bovine Serum Albumin [BSA] or BSA alone) prior to single culture embryonic stage records (Day-6: morula, early blastocyst, blastocyst; Day-7: expanding blastocyst; fully expanded blastocysts) and cryopreservation. Retained metabolite signals (6111) were analyzed as a function of pregnancy at Day-40, Day-62 and birth in a combinatorial block study with all fixed factors. We identified 34 accumulated metabolites through 511 blocks, 198 for birth, 166 for Day-62 and 147 for Day-40. The relative abundance of metabolites was higher within blocks from non-pregnant (460) than from pregnant (51) embryos. Taxonomy classified lipids (12 fatty acids and derivatives; 224 blocks), amino acids (12) and derivatives (3) (186 blocks), benzenoids (4; 58 blocks), tri-carboxylic acids (2; 41 blocks) and 5-Hydroxy-l-tryptophan (2 blocks). Some metabolites were effective as single biomarkers in 95 blocks (Receiver Operating Characteristic – Area Under the Curve [ROC-AUC]: 0.700–1.000). In contrast, more accurate predictions within the largest data sets were obtained with combinations of 2, 3 and 4 single metabolites in 206 blocks (ROC-AUC = 0.800–1.000). Pregnancy-prone embryos consumed more amino acids and citric acid, and depleted less lipids and cis-aconitic acid. Big metabolic differences between embryos support efficient pregnancy and birth prediction when analyzed in discriminant conditions.

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Tola, Adesola J., Amal Jaballi, Hugo Germain e Tagnon D. Missihoun. "Recent Development on Plant Aldehyde Dehydrogenase Enzymes and Their Functions in Plant Development and Stress Signaling". Genes 12, n. 1 (31 dicembre 2020): 51. http://dx.doi.org/10.3390/genes12010051.

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Abiotic and biotic stresses induce the formation of reactive oxygen species (ROS), which subsequently causes the excessive accumulation of aldehydes in cells. Stress-derived aldehydes are commonly designated as reactive electrophile species (RES) as a result of the presence of an electrophilic α, β-unsaturated carbonyl group. Aldehyde dehydrogenases (ALDHs) are NAD(P)+-dependent enzymes that metabolize a wide range of endogenous and exogenous aliphatic and aromatic aldehyde molecules by oxidizing them to their corresponding carboxylic acids. The ALDH enzymes are found in nearly all organisms, and plants contain fourteen ALDH protein families. In this review, we performed a critical analysis of the research reports over the last decade on plant ALDHs. Newly discovered roles for these enzymes in metabolism, signaling and development have been highlighted and discussed. We concluded with suggestions for future investigations to exploit the potential of these enzymes in biotechnology and to improve our current knowledge about these enzymes in gene signaling and plant development.

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Šindelář, Karel, Jiří Holubek, Emil Svátek, Miroslav Ryska, Martin Valchář e Miroslav Protiva. "Butaclamol-like neuroleptic agents: Synthesis of 1-(11H-dibenz[b,f]-1,4-oxathiepin-11-yl)methyl-4-isobutylpiperidin-4-ol and of some related compounds". Collection of Czechoslovak Chemical Communications 50, n. 7 (1985): 1484–97. http://dx.doi.org/10.1135/cccc19851484.

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1-(11H-Dibenz[b,f]-1,4-oxathiepin-11-yl)methyl-4-piperidone (XIII), which was obtained from 11H-dibenz[b,f]-1,4-oxathiepin-11-carboxylic acid (VIII) in four steps, was treated with isobutylmagnesium bromide and gave the title compound V in addition to the prevailing quantity of the secondary alcohol VI, i.e. the product of reduction. Synthesis of a series of trisubstituted benzyl phenyl sulfide derivatives XVIII-XXIV, XXVI-XXXI is described; these compounds are potential intermediates in the preparation of 11H-dibenz[b,f]-1,4-oxathiepinacetic acids XVI and XVII. Chloromethylation of 11H-dibenz[b,f]-1,4-oxathiepin (VII) and two further usual steps gave an acid to which structure XVI is assigned. Compound V is an open model of "oxathiaisobutaclamol" and in agreement with this fact it behaves like a neuroleptic agent: it increases the turnover and metabolism of dopamine in the rat brain striatum which is manifested by a significant rise of homovanillic acid level.

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