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Results 701 - 750 of 1414
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Munné-Bosch Sergi - - 2009
The goal of the present research was to obtain new insights into the mechanisms underlying drought stress resistance in plants. Specifically, we evaluated changes in the expression of genes encoding enzymes involved in isoprenoid biosynthesis, together with the levels of the corresponding metabolites (chlorophylls, carotenoids, tocopherols and abscisic acid), in ...
Zhou Hui - - 2008
Resorcylic acid lactones represent a unique class of fungal polyketides and display a wide range of biological activities, such as nanomolar inhibitors of Hsp90 and MAP kinase. The biosynthesis of these compounds is proposed to involve two fungal polyketide synthases (PKS) that function collaboratively to yield a 14-membered macrolactone with ...
Pankewitz Florian - - 2008
Polyketides are known to be used by insects for pheromone communication and defence against enemies. Although in microorganisms (fungi, bacteria) and plants polyketide biogenesis is known to be catalysed by polyketide synthases (PKS), no insect PKS involved in biosynthesis of pheromones or defensive compounds have yet been found. Polyketides detected ...
Sheoran Anita - - 2008
Thiocoraline is a thiodepsipeptide antitumor agent that belongs to the family of bisintercalator natural products that bind duplex DNA through their two planar intercalating moieties. In thiocoraline, the 3-hydroxyquinaldic acid (3HQA) chromophores required for intercalation are derived from L-Trp. We have expressed the Micromonospora sp. ML1 tryptophan 2,3-dioxygenase(TDO) TioF, purified ...
Palme Klaus - - 2008
There is much interest in understanding the pathways that trigger biosynthesis of the plant hormone auxin. In this issue, Stepanova et al. (2008) and Tao et al. (2008) reveal that a small family of tryptophan aminotransferases catalyze formation of indole-3-pyruvic acid (IPA) from L-tryptophan (L-Trp), the first step in a ...
Schaller Florian - - 2008
Jasmonates are derived from oxygenated fatty acids (oxylipins) via the octadecanoid pathway and are characterized by a pentacyclic ring structure. They have regulatory functions as signaling molecules in plant development and adaptation to environmental stress. Recently, we solved the structure of allene oxide cyclase 2 (AOC2) of Arabidopsis thaliana, which ...
Luo Yinggang - - 2008
Neocarzinostatin, a clinical anticancer drug, is the archetypal member of the chromoprotein family of enediyne antitumor antibiotics that are composed of a nonprotein chromophore and an apoprotein. The neocarzinostatin chromophore consists of a nine-membered enediyne core, a deoxyaminosugar, and a naphthoic acid moiety. We have previously cloned and sequenced the ...
Wang Wenya - - 2009
Catalyzed by phenylalanine ammonia-lyase from Rhodotorula glutinis, 2% trans-cinnamic acid and 0.5 mol/l (15NH4)2SO4 was bioconverted to 15NL-phenylalanine. The yield and the purity of 15NL-phenylalanine reached 71 and 99.3%, respectively. The results showed that 96% of 15N was labeled on the L-phenylalanine and 88% of (15NH4)2SO4 was recovered. The present ...
Simirgiotis Mario J - - 2008
Bioassay-guided fractionation of the methanolic extracts of the pulp and seeds of the fruits of Syzygium samarangense Merr. & Perry (Blume) led to the identification of four cytotoxic compounds and eight antioxidants on the basis of HPLC-PDA analysis, MS, and various NMR spectroscopic techniques. Three C-methylated chalcones, 2',4'-dihydroxy-3',5'-dimethyl-6'-methoxychalcone (1), 2',4'-dihydroxy-3'-methyl-6'-methoxychalcone ...
Luttik M A H - - 2008
A quantitative analysis of the impact of feedback inhibition on aromatic amino acid biosynthesis was performed in chemostat cultures of Saccharomyces cerevisiae. Introduction of a tyrosine-insensitive allele of ARO4 (encoding 3-deoxy-d-arabino-heptulosonate-7-phosphate synthase) caused a three-fold increase of intracellular phenylalanine and tyrosine concentrations. These amino acids were not detected extracellularly. However, ...
Tsfadia Oren - - 2008
We combine the use of labeled precursors with enzyme inhibitors to decipher the biosynthetic pathway of pheromone biosynthesis and the rate-limiting step/s that are regulated by pheromone biosynthesis activating neuropeptide (PBAN). We demonstrate that Plodia interpunctella is able to utilize hexadecanoic acid, and to a lesser extent tetradecanoic acid, for ...
Xia Guoqing - - 2008
Wall teichoic acid (WTA) contributes profoundly to the virulence of Staphylococcus aureus. The successful in vitro reconstitution of poly-ribitolphosphate WTA biosynthesis using recombinant enzymes sheds new light on WTA enzymology and paves the way for developing new antibiotics that target WTA biosynthesis, as discussed in Brown et al. in a ...
Humljan J - - 2008
UDP-N-acetylmuramic acid (UDP-MurNAc) is a substrate of MurC, an important enzyme in the intracellular pathway of bacterial peptidoglycan biosynthesis. Various approaches towards preparation of UDP-MurNAc have been published but these synthetic preparations were shown to include many problematic steps. An optimization study with the focus on muramyl phosphate and UMP-morpholidate ...
Mirza Sajjad Hussain - - 2008
OBJECTIVE: To find out the frequency of low-level quinolone-resistance in Multi-Drug Resistant (MDR) typhoid using nalidixic acid screening disc. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Armed Forces Institute of Pathology, Rawalpindi, from January 2005 to December 2005. MATERIALS AND METHODS: Blood was obtained from suspected cases of ...
Kaliszewski PaweĊ‚ - - 2008
Rsp5 is a conserved ubiquitin ligase involved in regulation of numerous cellular processes. A growing number of publications describing new functions of the ligase have appeared in recent years. Rsp5 was shown to be involved in the control of intracellular trafficking of proteins via endocytosis and multivesicular body sorting. Moreover, ...
Heckmann Lars-Henrik - - 2008
Eicosanoids are biologically active, oxygenated metabolites of three C20 polyunsaturated fatty acids. They act as signalling molecules within the autocrine or paracrine system in both vertebrates and invertebrates mainly functioning as important mediators in reproduction, the immune system and ion transport. The biosynthesis of eicosanoids has been intensively studied in ...
Goodman C D - - 2008
Fatty acid biosynthesis pathways in protozoan parasites are reviewed with a view to targeting this metabolism for drug therapy. The type II fatty acid biosynthesis pathways derived from bacteria in protozoan relict plastids and mitochondria are examined in different groups with emphasis on apicomplexa. The suitability of different enzymes from ...
Yurlova N A - - 2008
Dothideaceous black yeast-like fungi (BYF) are known to synthesise DHN-melanin that is inhibited by the systemic fungicide tricyclazole. The final step of the DHN melanin pathway is the conjoining of 1,8-DHN molecules to form the melanin polymer. There are several candidate enzymes for this step, including phenoloxidases such as tyrosinase ...
Liénard Marjorie A - - 2008
Moths have evolved highly successful mating systems, relying on species-specific mixtures of sex pheromone components for long-distance mate communication. Acyl-CoA desaturases are key enzymes in the biosynthesis of these compounds and to a large extent they account for the great diversity of pheromone structures in Lepidoptera. A novel desaturase gene ...
Gratraud Paul P Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier II et I, CNRS, UMR 5235, case 107, Place Eugène Bataillon, 34095 Montpellier Cedex 05, - - 2008
The antimalarial agents NAS-91 and NAS-21 were found to express potent antimycobacterial activity, NAS-91 being more active than NAS-21. They partially inhibited mycolic acid biosynthesis and profoundly altered oleic acid production. The development of a cell-free assay for Delta 9-desaturase activity allowed direct demonstration of the inhibition of oleic acid ...
Godio Ramiro P - - 2007
The basidiomycete Hypholoma sublateritium produces the triterpenoid antitumor clavaric acid, an inhibitor of the human Ras-farnesyl transferase. The H. sublateritium squalene epoxidase gene (erg1) has been cloned and shown to encode a flavoprotein monooxygenase that requires FAD, NADPH, and P450 cofactors. Silencing of the erg1 gene in H. sublateritium using ...
Arruda Denise Costa - - 2008
The isoprenoid metabolic pathway in protozoa of the Leishmania genus exhibits distinctive characteristics. These parasites, as well as other members of the Trypanosomatidae family, synthesize ergosterol, instead of cholesterol, as the main membrane sterol lipid. Leishmania has been shown to utilize leucine, instead of acetate as the main precursor for ...
Ohashi Yoshiaki - - 2008
Metabolic changes in response to histidine starvation were observed in histidine-auxotrophic Escherichia coli using a capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS)-based metabolomics technique. Prior to the analysis, we prepared an E. coli metabolome list of 727 metabolites reported in the literature. An improved method for metabolite extraction was developed, which ...
Abad José-Luis - - 2007
The stereochemical course of the Delta13 desaturation involved in the biosynthesis of Thaumetopoea pityocampa sex pheromone was studied using stereotopically labeled and tagged palmitic acids as metabolic probes. In the synthetic pathway, a functionalized acetylene common synthon was used for introducing the four deuterium tags. Further coupling of the tetradeuterated ...
AbouZid Sameh - - 2007
Thiophene A and thiophene A diol are the major polyacetylenes isolated from the hairy roots of Ambrosia maritima (Asteraceae) cultured under continuous light irradiation. The biosynthesis of thiophene A was studied using [1-(13)C]-, [2-(13)C]-, [1,2-(13)C]-acetates. The biosynthesis of thiarubrine A, produced by hairy roots cultured in the dark, was studied ...
Garscha Ulrike - - 2007
Aspergillus sp. contain ppoA, ppoB, and ppoC genes, which code for fatty acid oxygenases with homology to fungal linoleate 7,8-diol synthases (7,8-LDS) and cyclooxygenases. Our objective was to identify these enzymes, as ppo gene replacements show critical developmental aberrancies in sporulation and pathogenicity in the human pathogen Aspergillus fumigatus and ...
Teichmann Beate - - 2007
The phytopathogenic basidiomycetous fungus Ustilago maydis secretes large amounts of the glycolipid biosurfactant ustilagic acid (UA). UA consists of 15,16-dihydroxypalmitic or 2,15,16-trihydroxypalmitic acid, which is O-glycosidically linked to cellobiose at its terminal hydroxyl group. In addition, the cellobiose moiety is acetylated and acylated with a short-chain hydroxy fatty acid. We ...
Schneider Kathrin - - 2007
In the genome of Bacillus amyloliquefaciens FZB42, three operons pks1, pks2, and pks3 were identified which encode the biosynthesis of polyketides. pks1 and pks3 have been attributed to the production of bacillaene and difficidin/oxydifficidin, respectively, while the pks2 product remained hitherto unknown. Mass spectrometric analysis of the culture filtrates of ...
Morar Mariya - - 2007
Genes responsible for the generation of 3-dehydroquinate (DHQ), an early metabolite in the established shikimic pathway of aromatic amino acid biosynthesis, are absent in most euryarchaeotes. Alternative gene products, Mj0400 and Mj1249, have been identified in Methanocaldococcus jannaschii as the enzymes involved in the synthesis of DHQ. 2-Amino-3,7-dideoxy-d-threo-hept-6-ulosonic acid (ADH) ...
Wright H Tonie - - 2007
The fatty acid biosynthesis pathway is an attractive but still largely unexploited target for the development of new antibacterial agents. The extended use of the antituberculosis drug isoniazid and the antiseptic triclosan, which are inhibitors of fatty acid biosynthesis, validates this pathway as a target for antibacterial development. Differences in ...
Nasution Uly - - 2008
The relation between central metabolism and the penicillin biosynthesis pathway in Penicillium chrysogenum was studied by manipulating the steady-state flux in both pathways. A high producing industrial strain was cultivated at a growth rate mu=0.05 h(-1) in glucose-limited chemostat cultures, both under penicillin-G producing and non-producing conditions. Non-producing conditions were ...
Goller Stephan - - 2007
The hydrocarbons (3Z,6Z,9Z)-3,6,9-octadecatriene (3Z,6Z,9Z-18:H) and (3Z,6Z,9Z)-3,6,9-nonadecatriene (3Z,6Z,9Z-19:H) constitute the pheromone of the winter moth, Erannis bajaria. These compounds belong to a large group of lepidopteran pheromones which consist of unsaturated hydrocarbons and their corresponding oxygenated derivatives. The biosynthesis of such hydrocarbons with an odd number of carbons in the chain ...
Lopes Adriana A - - 2007
The biosynthesis of (2S)-2-methyl-2-(4'-methyl-3'-pentenyl)-8-(3''-methyl-2-butenyl)-2H-1-benzopyran-6-carboxylic acid (gaudichaudianic acid), the major metabolite in leaves and roots of Piper gaudichaudianum Kunth (Piperaceae), has been investigated employing [1-(13)C]-D-glucose as precursor. The labelling pattern in the isolated gaudichaudianic acid was determined by quantitative (13)C NMR spectroscopy analysis and was consistent with involvement of both mevalonic ...
Sule Olajumoke - - 2007
We questioned 62 dermatology outpatients with atopic eczema and Staphylococcus aureus colonisation regarding their use of topical preparations containing fusidic acid during the previous 6 months as well as the pattern of any such use. Recent exposure to topical fusidic acid was significantly correlated with the presence of fusidic acid-resistant ...
Eltahlawy H S - - 2007
The regulation of pheromone biosynthesis by the neuropeptide PBAN in the Z strain of the European corn borer, Ostrinia nubilalis, was investigated using labeled intermediates. Injection of radiolabeled acetate showed PBAN did not influence the de novo synthesis of saturated fatty acids in the gland. When deuterium-labeled myristic acid was ...
Aznar E - - 2007
Detection of Salmonella spp. isolates showing decreased susceptibility to fluoroquinolones has become important owing to the increasing prevalence of these strains and their association with treatment failure. Nalidixic acid agar dilution, nalidixic acid disk diffusion, MicroScan automated system and real-time polymerase chain reaction (PCR) (LightCycler) followed by melting temperature (Tm) ...
Pfleger Brian F - - 2007
Recently, iron acquisition and, more specifically, enzymes involved in siderophore biosynthesis have become attractive targets for discovery of new antibiotics. Accordingly, targeted inhibition of the biosynthesis of petrobactin, a virulence-associated siderophore encoded by the asb locus in Bacillus anthracis, may hold promise as a potential therapy against anthrax. This study ...
Gokhale Rajesh S - - 2007
The cell envelope of Mycobacterium tuberculosis (Mtb) is a treasure house of a variety of biologically active molecules with fascinating architectures. The decoding of the genetic blueprint of Mtb in recent years has provided the impetus for dissecting the metabolic pathways involved in the biosynthesis of lipidic metabolites. The focus ...
Stanley David - - 2007
Eighteen pharmaceutical inhibitors of eicosanoid biosynthesis were tested for their effects on gypsy moth, Lymantria dispar and its susceptibility to the nucleopoly-hedrovirus LdMNPV. None of the inhibitors tested had any detrimental effects upon larval growth and development. Treatment with nine inhibitor/NPV combinations (e.g., bromophenacylbromide, clotrimazole, dexamethasone, esculetin, flufenamic acid, indomethacin, ...
Norén T - - 2007
In silico, we identified fusA (2,067 bp) in Clostridium difficile 630. Sequencing of fusA in posttherapy fusidic acid-resistant C. difficile isolates from 12 patients with C. difficile-associated diarrhea (CDAD) identified fusA mutations, one or two nonsynonymous substitutions, or in one case a deletion of one codon associated with resistance. Five ...
Abad José-Luis - - 2007
The synthesis of two hexadeuterated palmitic acids differing in the position of the diagnostic labels, and their use to decipher the cryptoregiochemistry of a Delta13 desaturation are described. A dithiane and a triple bond functionalities were used to introduce the diagnostic (C13 or C14) and tagging (C8 and C9) labels, ...
Tangprasittipap Amornrat - - 2007
Of 23 strains of halotolerant (up to 12% w/v NaCl) photosynthetic bacteria isolated from various sources, one isolate, SH5, accumulated intracellular 5-aminolevulinic acid (ALA) at 0.45 microg/g dry cell wt (DCW) growing aerobically in the dark. The strain was identified as Rhodobacter sphaeroides using 16S rDNA sequencing. Biosynthesis of ALA ...
Schuhmann Tim - - 2007
The microbial macrolides bafilomycin A1, B, and concanamycin A from Streptomyces spp. are potent and specific inhibitors of V-ATPases. The question of the biosynthetic origin of the two uncommon "glycolate units" of each of the macrolide structures was addressed by feeding experiments with stereospecifically 13C-labeled precursors. Our studies clearly indicate ...
Edima Hélène Carole - - 2007
A selective medium was proposed for isolating the species Carnobacterium maltaromaticum from cheeses. This medium, named CM, was elaborated using combinations of three antibiotics (gentamicin, nalidixic acid, vancomycin) and alkaline pH value (8.8). An experimental design (Doehlert matrix) was drawn up to optimize the experimental conditions of the preparation of ...
Zerbe Philipp - - 2007
The pathway of jasmonic acid (JA) biosynthesis was established in the 1980s by Vick and Zimmerman but, until now, the preparative biosynthesis of the jasmonic acid precursors 12-oxo-phytodienoic acid (OPDA) and 3-oxo-2-[2'-pentenyl]-cyclopentan-1-octanoic acid (OPC-8:0) in their endogenous and biologically relevant cis(+)-configuration was only possible in small amounts and had to ...
Sato Masaru - - 2006
D-Alanine-D-alanine ligase (Ddl) and its mutants maintain the biosynthesis of peptidoglycan, and the substrate specificity of Ddls partially affects the resistance mechanism of vancomycin-resistant enterococci. Through investigation of Ddls, Ddl from Thermotoga maritima ATCC 43589 showed novel characteristics, vis. thermostability up to 90 degrees C and broad substrate specificity toward ...
Asahina Shinji - - 2006
Polysialoglycoprotein (PSGP) in salmonid fish egg is a unique glycoprotein bearing alpha2,8-linked polysialic acid (polySia) on its O-linked glycans. Biosynthesis of the polySia chains is developmentally regulated and only occurs at later stage of oogenesis. Two alpha2,8-polysialyltransferases (alpha2,8-polySTs), PST (ST8Sia IV) and STX (ST8Sia II), responsible for the biosynthesis of ...
Chen Fang - - 2006
Genes encoding seven enzymes of the monolignol pathway were independently downregulated in alfalfa (Medicago sativa) using antisense and/or RNA interference. In each case, total flux into lignin was reduced, with the largest effects arising from the downregulation of earlier enzymes in the pathway. The downregulation of l-phenylalanine ammonia-lyase, 4-coumarate 3-hydroxylase, ...
Porat Iris - - 2006
Methanococcus maripaludis is a strictly anaerobic, methane-producing archaeon and facultative autotroph capable of biosynthesizing all the amino acids and vitamins required for growth. In this work, the novel 6-deoxy-5-ketofructose-1-phosphate (DKFP) pathway for the biosynthesis of aromatic amino acids (AroAAs) and p-aminobenzoic acid (PABA) was demonstrated in M. maripaludis. Moreover, PABA ...
Keeling Christopher I - - 2006
Diterpene resin acids are a significant component of conifer oleoresin, which is a viscous mixture of terpenoids present constitutively or inducibly upon herbivore or pathogen attack and comprises one form of chemical resistance to such attacks. This review focuses on the recent discoveries in the chemistry, biosynthesis, molecular biology, regulation, ...
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