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Results 451 - 500 of 1857
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Kino Kuniki - - 2007
Broad specificity amino acid racemase (E.C. 5.1.1.10) from Pseudomonas putida IFO 12996 (BAR) is a unique racemase because of its broad substrate specificity. BAR has been considered as a possible catalyst which directly converts inexpensive L-amino acids to DL-amino acid racemates. The gene encoding BAR was cloned to utilize BAR ...
Taguchi Fumiko - - 2006
Pseudomonas syringae pv. tabaci 6605 possesses a genetic region involved in flagellin glycosylation. This region is composed of three open reading frames: orf1, orf2, and orf3. Our previous study revealed that orf1 and orf2 encode glycosyltransferases; on the other hand, orf3 has no role in posttranslational modification of flagellin. Although ...
Kim Il-Sup - - 2006
To investigate the tolerance factor of Saccharomyces cerevisiae KNU5377 against various types of environmental stress during fermentation, we identified the protein that is upregulated at high temperatures. The highly upregulated protein was high-score-matched as a cytoplasmic peptidyl-prolyl cis-trans isomerase, cyclophilin (Cpr1p), by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). ...
Liu Yi - - 2006
Typically during human immunodeficiency virus type 1 (HIV-1) infection, a nearly homogeneous viral population first emerges and then diversifies over time due to selective forces that are poorly understood. To identify these forces, we conducted an intensive longitudinal study of viral genetic changes and T-cell immunity in one subject at ...
Sonawane Avinash M - - 2006
Pseudomonas putida KT2440 metabolizes a wide range of carbon and nitrogen sources, including many amino acids. In this study, a sigma54-dependent two-component system that controls the uptake and metabolism of acidic amino acids was identified. The system (designated aau, for acidic amino acid utilization) involves a sensor histidine kinase, AauS, ...
Reeve Wayne G - - 2006
Sinorhizobium medicae WR101 was identified as a mutant of WSM419 that contained a minitransposon-induced transcriptional gusA fusion activated at least 20-fold at pH 5.7. The expression of this fusion in moderately acid conditions was dependent on the calcium concentration; increasing the calcium concentration to enhance cell growth and survival in ...
Ritsema Tita - - 2006
Fructans are fructose polymers that are synthesized from sucrose by fructosyltransferases. Fructosyltransferases are present in unrelated plant families suggesting a polyphyletic origin for their transglycosylation activity. Based on sequence comparisons and enzymatic properties, fructosyltransferases are proposed to have evolved from vacuolar invertases. Between 1% and 5% of the total activity ...
Klose Jana - - 2006
The transition from yeast-like to filamentous growth in the biotrophic fungal phytopathogen Ustilago maydis is a crucial event for pathogenesis. Previously, we showed that fatty acids induce filamentation in U. maydis and that the resulting hyphal cells resemble the infectious filaments observed in planta. To explore the potential metabolic role ...
Rizzo William B - - 2007
Sjögren-Larsson syndrome (SLS) is an inherited neurocutaneous disorder caused by mutations in the ALDH3A2 gene that encodes fatty aldehyde dehydrogenase (FALDH), an enzyme that catalyzes the oxidation of fatty aldehyde to fatty acid. Affected patients display ichthyosis, mental retardation and spastic diplegia. More than 70 mutations in ALDH3A2 have been ...
Ring Michael W - - 2006
Iso-fatty acids (FAs) are the dominant FA family in all myxobacteria analyzed. Furthermore, it was postulated that iso-FAs or compounds derived thereof are involved in fruiting body formation in Myxococcus xanthus, since mutants with a reduced level of iso-FA due to a reduced level of the precursor isovaleryl-CoA, are delayed ...
Alemi Mansour - - 2007
Deletions within the mitochondrial DNA (mtDNA) cause Kearns Sayre syndrome (KSS) and chronic progressive external opthalmoplegia (CPEO). The clinical signs of KSS include muscle weakness, heart block, pigmentary retinopathy, ataxia, deafness, short stature, and dementia. The identical deletions occur and rise exponentially as humans age, particularly in substantia nigra. Deletions ...
Murakami Shizuka - - 2006
We previously reported the mode of inhibition of DNA polymerase beta (pol. beta) by long chain fatty acids and a bile acid, involving binding analyses to the N-terminal 8-kDa DNA binding domain. Here we describe a site-directed mutational analysis in which the key amino acids (L11, K35, H51, K60, L77, ...
Simões T - - 2006
The Saccharomyces cerevisiae SPI1 gene encodes a member of the glycosylphosphatidylinositol-anchored cell wall protein family. In this work we show results indicating that SPI1 expression protects the yeast cell from damage caused by weak acids used as food preservatives. This is documented by a less extended period of adaptation to ...
Piekarska Katarzyna - - 2006
Phagocytic cells form the first line of defense against infections by the human fungal pathogen Candida albicans. Recent in vitro gene expression data suggest that upon phagocytosis by macrophages, C. albicans reprograms its metabolism to convert fatty acids into glucose by inducing the enzymes of the glyoxylate cycle and fatty ...
Spassieva Stefka - - 2006
Lag1 (longevity assurance gene 1) homologues, a family of transmembrane proteins found in all eukaryotes, have been shown to be necessary for (dihydro)ceramide synthesis. All Lag1 homologues contain a highly conserved stretch of 52 amino acids known as the Lag1p motif. However, the functional significance of the conserved Lag1p motif ...
Rahman Abidur - - 2006
2,4-dichlorophenoxyacetic acid (2,4-D), a chemical analogue of indole-3-acetic acid (IAA), is widely used as a growth regulator and exogenous source of auxin. Because 2,4-D evokes physiological and molecular responses similar to those evoked by IAA, it is believed that they share a common response pathway. Here, we show that a ...
Franks A - - 2006
The marine epiphytic bacterium Pseudoalteromonas tunicata produces a range of extracellular secondary metabolites that inhibit an array of common fouling organisms, including fungi. In this study, we test the hypothesis that the ability to inhibit fungi provides P. tunicata with an advantage during colonization of a surface. Studies on a ...
Vedha-Peters Kavitha - - 2006
Using both rational and random mutagenesis, we have created the first known broad substrate range, nicotinamide cofactor dependent, and highly stereoselective d-amino acid dehydrogenase. This new enzyme is capable of producing d-amino acids via the reductive amination of the corresponding 2-keto acid with ammonia. This biocatalyst was the result of ...
Lisso Janina - - 2006
The tomato DWARF cytochrome P450 protein catalyzes the C-6 oxidation of 6-deoxo-castasterone to castasterone. The d(x) mutant does not produce a functional DWARF enzyme, and d(x) shoots display severe symptoms of brassinosteroid-deficiency. However, fruits express the CYP85A3 protein which compensates for the deficiency of the DWARF protein and produce bioactive ...
Ozimek Lukasz K - - 2006
Bacterial fructansucrase enzymes belong to glycoside hydrolase family 68 and catalyze transglycosylation reactions with sucrose, resulting in the synthesis of fructooligosaccharides and/or a fructan polymer. Significant differences in fructansucrase enzyme product specificities can be observed, i.e. in the type of polymer (levan or inulin) synthesized, and in the ratio of ...
Chang Shuo-Chin - - 2006
Malic enzyme catalyses the reduction of NADP+ to NADPH and the decarboxylation of L-malate to pyruvate through a general acid/base mechanism. Previous kinetic and structural studies differ in their interpretation of the amino acids responsible for the general acid/base mechanism. To resolve this discrepancy, we used site-directed mutagenesis and kinetic ...
Kubota Takaaki - - 2006
The biosynthesis of the antitumor antibiotic, ansamitocin, involves the assembly of a linear octaketide on the ansamitocin (asm) polyketide synthase (PKS), which is then cyclized to proansamitocin and further modified to the final product. In the first chain-extension step on the asm PKS, a stereocenter is generated which is then ...
Kralj Slavko - - 2006
Glucansucrases from lactic acid bacteria convert sucrose into various alpha-glucans that differ greatly with respect to the glucosidic bonds present (e.g. dextran, mutan, alternan and reuteran). This study aimed to identify the structural features of the reuteransucrase from Lactobacillus reuteri 121 (GTFA) that determine its reaction specificity. We here report ...
Gimmestad Martin - - 2006
Alginate is a linear copolymer of beta-d-mannuronic acid and its C-5-epimer, alpha-l-guluronic acid. During biosynthesis, the polymer is first made as mannuronan, and various fractions of the monomers are then epimerized to guluronic acid by mannuronan C-5-epimerases. The Azotobacter vinelandii genome encodes a family of seven extracellular such epimerases (AlgE1 ...
Qiao Xugang - - 2006
In trypanosomatids, endocytosis and exocytosis are restricted to the flagellar pocket (FP). The cysteine-rich acidic repetitive transmembrane (CRAM) protein is located at the FP of Trypanosoma brucei and potentially functions as a receptor or an essential component for lipoprotein uptake. We characterized sorting determinants involved in efficient trafficking of CRAM ...
Ito Hironori - - 2006
Arabidopsis (Arabidopsis thaliana) contains 15 genes encoding members of the pleiotropic drug resistance (PDR) family of ATP-binding cassette transporters. These proteins have been speculated to be involved in the detoxification of xenobiotics, however, little experimental support of this hypothesis has been obtained to date. Here we report our characterization of ...
da Silva Jack - - 2006
Analysis of the intensely studied HIV-1 gp120 V3 protein region reveals that the among-population mean site-specific frequency of an amino acid is a measure of its relative marginal fitness. This surprising result may arise if populations are displaced from mutation-selection equilibrium by fluctuating selection and if the probability of fixation ...
Tang Dingzhong - - 2006
We screened for mutants of Arabidopsis thaliana that displayed enhanced disease resistance to the powdery mildew pathogen Erysiphe cichoracearum and identified the edr3 mutant, which formed large gray lesions upon infection with E. cichoracearum and supported very little sporulation. The edr3-mediated disease resistance and cell death phenotypes were dependent on ...
Laurie-Berry Neva - - 2006
Many plant pathogens suppress antimicrobial defenses using virulence factors that modulate endogenous host defenses. The Pseudomonas syringae phytotoxin coronatine (COR) is believed to promote virulence by acting as a jasmonate analog, because COR-insensitive 1 (coil) Arabidopsis thaliana and tomato mutants are impaired in jasmonate signaling and exhibit reduced susceptibility to ...
Lalonde Robert - - 2006
Ataxic Rora(sg) (staggerer) mouse mutants, containing a deletion of the Rora gene which encodes a retinoid-like nuclear receptor, were compared to non-ataxic controls for concentrations of 5-hydroxytryptamine (HT), its main metabolite (5-hydroxy-indole acetic acid, 5HIAA), and its precursor (tryptophan) in cerebellum, brainstem, and forebrain. In Rora(sg) cerebellum, 5HT concentrations increased ...
MirAfzali Zahra - - 2006
The topology of association of the monotopic protein cyclooxygenase-2 (COX-2) with membranes has been examined using EPR spectroscopy of spin-labeled recombinant human COX-2. Twenty-four mutants, each containing a single free cysteine substituted for an amino acid in the COX-2 membrane binding domain were expressed using the baculovirus system and purified, ...
Flemming Dirk - - 2006
The NADH:ubiquinone oxidoreductase (complex I) from Escherichia coli is composed of 13 subunits called NuoA through NuoN and contains one FMN and 9 iron-sulfur clusters as redox groups. Electron transfer from NADH to ubiquinone is coupled with the translocation of protons across the membrane by a yet unknown mechanism. Redox-induced ...
Hildebrandt M A T - - 2007
Amino-acid substitutions, which result from common nonsynonymous (NS) polymorphisms, may dramatically alter the function of the encoded protein. Gaining insight into how these substitutions alter function is a step toward acquiring predictability. In this study, we incorporated gene resequencing, functional genomics, amino-acid characterization and crystal structure analysis for the cytosolic ...
Amiri-Jami Mitra - - 2006
Transposon Tn5 mutagenesis was used to generate random mutations in Shewanella baltica MAC1, a polyunsaturated fatty acid (PUFA)-producing bacterium. Three mutants produced 3-5 times more eicosapentaenoic acid (EPA 20:5 n-3) compared to the wild type at 10 degrees C. One of the mutants produced 0.3 mg EPA g(-1) when grown ...
Suwannakham Supaporn - - 2006
Propionibacterium acidipropionici produces propionic acid from glucose with acetic acid, succinic acid, and CO2 as byproducts. In this work, inactivation of ack gene, encoding acetate kinase (AK), by gene disruption and integrational mutagenesis was studied as a method to reduce acetate formation in propionic acid fermentation. The partial ack gene ...
Brock Trisha J - - 2006
Delta-9 desaturases, also known as stearoyl-CoA desaturases, are lipogenic enzymes responsible for the generation of vital components of membranes and energy storage molecules. We have identified a novel nuclear hormone receptor, NHR-80, that regulates delta-9 desaturase gene expression in Caenorhabditis elegans. Here we describe fatty acid compositions, lifespans, and gene ...
Ujike Makoto - - 2006
The C-terminal sequence of the cytoplasmic tail (CT) of influenza B haemagglutinin (BHA) consists of strictly conserved, hydrophobic amino acids, and the endmost C-terminal amino acid of the CT is Leu. To elucidate the role of this amino acid in the fusion activity of BHA (B/Kanagawa/73), site-specific mutant HAs were ...
Zhang Shuo - - 2006
A mutant of Mortierella alpina, JT-180, which is defective in its delta12 desaturase activity but exhibits enhanced activities of delta5 and delta6 desaturases, produced a high proportion (up to 80%) of odd-chain FA when grown on 3% n-heptadecane. Following growth of the mutant on n-heptadecane, three unusual odd-chain fatty acyl ...
Kunte Amit S - - 2006
SREBPs are membrane bound transcription factors that are crucial for normal lipid synthesis in animal cells. Here, we show that Drosophila lacking dSREBP die before the third larval instar. Mutant larvae exhibit pronounced growth defects prior to lethality, along with substantial deficits in the transcription of genes required for fatty ...
Shokri Atefeh - - 2006
At increasing glucose limitation, typical for fed-batch cultivation performance, cultivation of Escherichia coli (relA1) results in development of a lipid structure that radically differs from the wild type and is characterised by accumulation of neutral phospholipids and saturated fatty acids. The mutant can, furthermore, not change the level of cardiolipin, ...
Qu Zhiqiang - - 2006
Mutations in human bestrophin-1 (VMD2) are genetically linked to a juvenile form of macular degeneration and autosomal dominant vitreoretinochoroidopathy. Recently, it has been proposed that bestrophins are Cl- channels and that the putative second transmembrane domain participates in forming the bestrophin pore. However, the structural determinants of Cl- ion permeation ...
Johansson Louise - - 2006
Shikimic acid, which is produced in the aromatic amino acid pathway in plants and microorganisms, is an industrially interesting chiral starting material for the synthesis of many chemical substances, e.g. the influenza medicine Tamiflu. When produced by genetically modified Escherichia coli it has previously been found that carbon-rich conditions (e.g. ...
Barkan Lenore - - 2006
Leaf membrane lipids of the Arabidopsis (Arabidopsis thaliana) fatty acid biosynthesis 1 (fab1) mutant contain a 35% to 40% increase in the predominant saturated fatty acid 16:0, relative to wild type. This increase in membrane saturation is associated with loss of photosynthetic function and death of mutant plants at low ...
Merfort Marcel - - 2006
Gluconobacter oxydans DSM 2343 (ATCC 621H)catalyzes the oxidation of glucose to gluconic acid and subsequently to 5-keto-D-gluconic acid (5-KGA), a precursor of the industrially important L-(+)-tartaric acid. To further increase 5-KGA production in G. oxydans, the mutant strain MF1 was used. In this strain the membrane-bound gluconate-2-dehydrogenase activity, responsible for ...
Cristea Mirela - - 2006
Lipoxygenases with R stereospecificity have a conserved Gly residue, whereas (S)-lipoxygenases have an Ala residue. Site-directed mutagenesis has shown that these residues control position and S/R stereospecificity of oxygenation. Recombinant Mn-LO was expressed in Pichia pastoris, and its conserved Gly-316 residue was mutated to Ala, Ser, Val, and Thr. The ...
Kang Beom Ryong - - 2006
Certain plant growth-promoting bacteria, such as Pseudomonas fluorescens 89B61 and Bacillus pumilus SE34, secreted high levels of indole-3-acetic acid (IAA) in tryptophan-amended medium in stationary phase as determined by chromogenic analysis and high-performance liquid chromatography. Two other growth-promoting strains, P. chlororaphis O6 and Serratia marcescens 90-166, did not produce these ...
Hamamoto Hiromi H Biotechnology Research Center, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, - - 2006
Our previous studies revealed the species-based difference of CYP24A1-dependent vitamin D metabolism. Although human CYP24A1 catalyzes both C-23 and C-24 oxidation pathways, rat CYP24A1 shows almost no C-23 oxidation pathway. We tried to identify amino acid residues that cause the species-based difference by site-directed mutagenesis. In the putative substrate-binding regions, ...
Bakke Mikio - - 2006
D-amino acid oxidase (DAO) is of considerable practical importance, such as bioconversion and enzymatic assay. In this study, we succeeded in obtaining a thermostable mutant DAO from porcine kidney by a single amino acid substitution. This mutant enzyme, F42C, was stable at 55 degrees C, while the wild-type enzyme was ...
Bearson Shawn M D - - 2006
Since the stomach is a first line of defense for the host against ingested microorganisms, an ex vivo swine stomach contents (SSC) assay was developed to search for genes important for Salmonella enterica serovar Typhimurium survival in the hostile gastric environment. Initial characterization of the SSC assay (pH 3.87) using ...
Zhu Kun - - 2006
The double bond in anaerobic unsaturated fatty acid (UFA) biosynthesis is introduced by the FabA dehydratase/isomerase of the bacterial type II fatty acid biosynthetic pathway. A DeltafabA mutant of Pseudomonas aeruginosa grew aerobically, but required a UFA supplement for anaerobic growth. Wild-type cells produced 18:1Delta11 as the principal UFA, whereas ...
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