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Results 351 - 400 of 1856
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Kobayashi Takehiro - - 2008
Alport syndrome (AS) is caused by mutations in type IV collagen alpha3, alpha4, and alpha5 chains. The three chains form a heterotrimer. In this study, we introduced 12 kinds of missense and three kinds of nonsense mutations, corresponding to AS mutations, into the NC1 domain of alpha5(IV) and characterized the ...
Chaturvedi Ratnesh - - 2008
Systemic acquired resistance (SAR) is an inducible defense mechanism that is activated throughout the plant, subsequent to localized inoculation with a pathogen. The establishment of SAR requires translocation of an unknown signal from the pathogen-inoculated leaf to the distal organs, where salicylic acid-dependent defenses are activated. We demonstrate here that ...
Frank Thomas - - 2007
Two low phytic acid (lpa) rice mutant lines, Os-lpa-XS110-1 and Os-lpa-XS110-2, were grown together with their parent wild-type variety Xiushui 110 in four field trials. HPLC analysis of inositol phosphates in the seeds produced demonstrated that compared to the wild-type, the reduction in phytic acid content in Os-lpa-XS110-1 (-46%) was ...
Harada Akihito - - 2007
The positively charged lysine at the C-terminals of three long alpha-helices (5-15, 25-35, and 88-99) was replaced with alanine (K13A, K33A, K97A) or aspartic acid (K13D, K33D, K97D) in hen lysozyme by genetic engineering. The denaturation transition point (Tm) and Gibbs energy change Delta G of the mutant lysozymes decreased ...
Eisenhut Marion - - 2007
The observation that accumulation of the amino acid glycine is associated with strong growth inhibition or even death in cyanobacteria, plants and humans led to the hypothesis that glycine might act toxically if a certain threshold is exceeded. In this report, it is shown that Synechocystis PCC 6803 wild-type cells ...
Jones Jacob - - 2007
The alternative sigma factor RpoN is a key regulator in the acclimation of Pseudomonas to complex natural environments. In this study we show that RpoN is required for efficient colonization of sugar beet seedlings by the plant growth-promoting bacterium Pseudomonas fluorescens SBW25, and use phenotypic and bioinformatic approaches to profile ...
Makrantoni Vasso - - 2007
In Saccharomyces cerevisiae, the serine-threonine protein kinase activity of Dbf2p is required for tolerance to the weak organic acid sorbic acid. Here we show that Dbf2p is required for normal phosphorylation of the vacuolar H(+)-ATPase (V-ATPase) A and B subunits Vma1p and Vma2p. Loss of V-ATPase activity due to bafilomycin ...
Sobajima Hiroyuki - - 2007
The rice 12-oxophytodienoic acid reductase 1 gene (OsOPR1), isolated as a jasmonic acid (JA)-responsive gene, has been suggested to be involved in defense responses in rice. We identified a 19-base pair region that is essential to the JA-responsiveness of OsOPR1 by deletion and mutation analysis of the promoter by dual ...
Brown Alistair K AK School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, - - 2007
Mycolic acids are vital components of the Mycobacterium tuberculosis cell wall and are essential for survival. While most components of the fatty acid synthase-II (FAS-II) enzymic machinery that synthesizes these long chain alpha-alkyl, beta-hydroxy fatty acids have been identified, the gene encoding the beta-hydroxyacyl-acyl carrier protein (ACP) dehydratase activity has ...
Plumridge Andrew - - 2008
Resistance to sorbic and cinnamic acids is mediated by a phenylacrylic acid decarboxylase (PadA1) in Aspergillus niger. A. niger DeltapadA1 mutants are unable to decarboxylate sorbic and cinnamic acids, and the MIC of sorbic acid required to inhibit spore germination was reduced by approximately 50% in DeltapadA1 mutants.
Wadman, M.W.
Polyunsaturated fatty acids play a central role in all biological systems. They are constituents of the plasma membrane and serve as precursors to signaling molecules generated in response to external events. The conversion of polyunsaturated fatty acids into signaling molecules starts by the hydrolysis of fatty acids from phospholipid molecules ...
Tanaka Y - - 2008
AIM: The aim of this study was to investigate the detailed mechanisms of acid resistance in Vibrio parahaemolyticus. METHODS AND RESULTS: All 11 strains of V. parahaemolyticus survived lethal acidic conditions following acid adaptation, and accumulation of cadaverine was detected. The addition of lysine improved survival, suggesting that lysine decarboxylase ...
Laval Françoise - - 2008
Mycolic acids are major and specific lipid components of the cell envelope of mycobacteria that include the causative agents of tuberculosis and leprosy, Mycobacterium tuberculosis and Mycobacterium leprae, respectively. Subtle structural variations that are known to be crucial for both their virulence and the permeability of their cell envelope occur ...
Birosová Lucia - - 2007
Phenolic compounds are ubiquitous in plant foods, and they have been reported to have multiple biological effects. This study investigates the ability of derivatives of hydroxybenzoic and hydroxycinnamic acids to influence the development of ciprofloxacin resistance in the antibiotic-sensitive strain Salmonella enterica subsp. enterica serovar Typhimurium. We have found that ...
Wakao Setsuko - - 2008
Glucose-6-phosphate dehydrogenase (G6PDH) has been implicated in the supply of reduced nicotine amide cofactors for biochemical reactions and in modulating the redox state of cells. In plants, identification of its role is complicated due to the presence of several isoforms in the cytosol and plastids. Here we focus on G6PDHs ...
Chu Dominique - - 2008
This article reports on experimental evidence that an Escherichia coli nanR mutant shows inhibited growth in N-acetylneuraminic acid. This effect is prevented when inocula are grown in an excess of glucose, but not in an excess of glycerol. The nanATEK operon is controlled by catabolite repression, suggesting that diminished expression ...
Andolfatto Peter - - 2007
Several recent studies have estimated that a large fraction of amino acid divergence between species of Drosophila was fixed by positive selection, using statistical approaches based on the McDonald-Kreitman test. However, little is known about associated selection coefficients of beneficial amino acid mutations. Recurrent selective sweeps associated with adaptive substitutions ...
Desnoyers Serge - - 2007
Mutations that inactivate LET-767 are shown to affect growth, reproduction, and development in Caenorhabditis elegans. Sequence analysis indicates that LET-767 shares the highest homology with human types 3 and 12 17beta-hydroxysteroid dehydrogenases (17beta-HSD3 and 12). Using LET-767 transiently transfected into human embryonic kidney-293 cells, we have found that the enzyme ...
Fu Joseph Y - - 2007
In this work, we examined the possibility of improving ion-exchange adsorbent performance by nanoscale structuring of ligands into clusters of fixed size rather than a random distribution of individual charges. The calcium-depleted form of the protein alpha-lactalbumin, which displays a cluster of acidic amino acid residues, showed enhanced adsorption affinity ...
Lemke Edward A - - 2007
We genetically encoded the photocaged amino acid 4,5-dimethoxy-2-nitrobenzylserine (DMNB-Ser) in Saccharomyces cerevisiae in response to the amber nonsense codon TAG. This amino acid was converted to serine in living cells by irradiation with relatively low-energy blue light and was used to noninvasively photoactivate phosphorylation of the transcription factor Pho4, which ...
Lu Hsin-Lin - - 2008
The 570-amino acid membrane form of IL-1RAcP (mIL-1RAcP) plays a pivotal role in the IL-1 signal transduction and response. We have identified another membrane form of IL-1RAcP with 687 amino acids (named as mIL-1RAcP687 hereon). Its except the last amino acid N-terminal 448 amino acid portion, containing three extracellular immunoglobulin ...
Zeng Xiaomei X Department of Biological Sciences, Columbia University, New York, New York 10027, - - 2007
Atp6p (subunit 6) of the Saccharomyces cerevisiae mitochondrial ATPase is synthesized with an N-terminal 10-amino acid presequence that is cleaved during assembly of the complex. This study has examined the role of the Atp6p presequence in the function and assembly of the ATPase complex. Two mutants were constructed in which ...
Salas Joaquín J - - 2008
In this study, we have biochemically characterized the high-stearic sunflower (Helianthus annuus L.) mutant CAS-14. This mutant displays an abnormal fatty acid composition along the length of the seed when grown at high temperatures. Thus, at the expense of oleate and linoleate, CAS-14 seeds present an increasing axial gradient of ...
Mène-Saffrané Laurent - - 2007
Malondialdehyde (MDA) is a small, ubiquitous, and potentially toxic aldehyde that is produced in vivo by lipid oxidation and that is able to affect gene expression. Tocopherol deficiency in the vitamin E2 mutant vte2-1 of Arabidopsis thaliana leads to massive lipid oxidation and MDA accumulation shortly after germination. MDA accumulation ...
Makino Yoshihide - - 2007
Phenylacetaldehyde reductase (PAR) from Rhodococcus sp. ST-10 is useful for chiral alcohol production because of its broad substrate specificity and high stereoselectivity. The conversion of ketones into alcohols by PAR requires the coenzyme NADH. PAR can regenerate NADH by oxidizing additional alcohols, especially 2-propanol. However, substrate conversion by wild-type PAR ...
Araki Hiroyuki - - 2007
cis-6-Hexadecenoic acid is a major component of human sebaceous lipids that is involved in skin self-sterilization and atopic dermatitis amelioration. It can be prepared by hydrolysis of isopropyl cis-6-hexadecenoate produced by resting cells of Rhodococcus sp. strain KSM-MT66. To devise an economical industrial-scale process for the production of this rare ...
Letzel Tobias - - 2007
Infectious bursal disease virus (IBDV), a member of the family Birnaviridae, is responsible for a highly contagious and economically important disease causing immunosuppression in chickens. IBDV variants isolated in the United States exhibit antigenic drift affecting neutralizing epitopes in the capsid protein VP2. To understand antigenic determinants of the virus, ...
Hu Mei-Rong - - 2007
In order to improve the laccase activity, mutant libraries are constructed through ethyl methane sulfonate-based (EMS) random mutagenesis. Mutagenesis improved expression 3.7-fold to 144 mgl(-1) laccase in yeast, together with a 1.4-fold increase in K(cat). Thus, the total activity is enhanced 5-fold for 2,2'-azino-bis 3-ethylbenzothiaoline-6-sulfonic acid (ABTS). In the presence ...
Ka Chandran - - 2007
In the present study, we correlate homozygosity for the very recently identified HJV p.R176C substitution with a juvenile hemochromatosis phenotype. We also show that the p.R176C variant fails to up-regulate the hepcidin promoter activity. Altogether, our results definitively show the R176C amino-acid change to be a novel hemojuvelin loss-of-function mutation.
Ghugtyal Vikram - - 2007
After glycosylphosphatidylinositols (GPIs) are added to GPI proteins of Saccharomyces cerevisiae, the fatty acid in sn-2 of the diacylglycerol moiety can be replaced by a C26:0 fatty acid by a deacylation-reacylation cycle catalysed by Per1p and Gup1p. Furthermore the diacylglycerol moiety of the yeast GPI anchor can also be replaced ...
Senoh Mitsutoshi - - 2008
Vibrio vulnificus, an opportunistic human pathogen causing fetal septicemia, produces a 50-kDa pore-forming toxin as a virulence factor. This toxin consists of 451 amino acid residues; however, there are two types of this toxin on the basis of the difference of some amino acid residues, type 1 (Leu(281), Ser(415), Asn(435)/Asp(435), ...
Kasrayan Alex - - 2007
A number of model structures of the CalA suggested by comparative modeling were tested by site-directed mutagenesis. Enzyme variants were created where amino acids predicted to play key roles for the lipase activity in the different models were replaced by an inert amino acid (alanine). The results from activity measurements ...
Chayakulkeeree Methee - - 2007
Fatty acid synthase in the yeast Cryptococcus neoformans is composed of two subunits encoded by FAS1 and FAS2 genes. We inserted a copper-regulated promoter (P(CTR4-2)) to regulate FAS1 and FAS2 expression in Cryptococcus neoformans (strains P(CTR4-2)/FAS1 and P(CTR4-2)/FAS2, respectively). Both mutants showed growth rates similar to those of the wild ...
Liu YongZhong - - 2007
'Fengjiewancheng' (FW) (Citrus sinensis), a bud sport of 'Fengjie 72-1' navel orange (FJ), ripens one month later than its parental line. Differences in sugar and acid content and the transcript level of sucrose-and citric-metabolic enzymes for the two cultivars were investigated during fruit ripening. Results showed that both sugar and ...
Suzuki Yoshiyuki - - 2007
Natural selection operating on amino acid substitution at single amino acid sites can be detected by comparing the rates of synonymous (r(S)) and nonsynonymous (r(N)) nucleotide substitution at single codon sites. Amino acid substitutions can be classified as conservative or radical according to whether they retain the properties of the ...
Shi Jinrui - - 2007
Phytic acid in cereal grains and oilseeds is poorly digested by monogastric animals and negatively affects animal nutrition and the environment. However, breeding programs involving mutants with less phytic acid and more inorganic phosphate (P(i)) have been frustrated by undesirable agronomic characteristics associated with the phytic acid-reducing mutations. We show ...
Jennison Amy V - - 2007
The stationary-phase acid-resistance pathways of Shigella flexneri 2457T have not previously been studied. The two acid-resistance systems, the glutamate-dependent acid-resistance (GDAR) and the oxidative pathways, reported elsewhere for Escherichia coli and S. flexneri 3136, were both detected in S. flexneri 2457T. However, S. flexneri 2457T cells grown overnight under fermentative ...
Vieira Jorge - - 2007
In this work we perform a comparative study on the location of positively selected sites (those likely responsible for defining specificity differences) at the S-RNase gene, the pistil component of the gametophytic self-incompatibility system. For Plantaginaceae and Rosaceae (Prunus and Pyrus/Malus) this is the first study of this kind. A ...
Hoffmann Mareike - - 2007
Fatty acid desaturases catalyze the introduction of double bonds at specific positions of an acyl chain and are categorized according to their substrate specificity and regioselectivity. The current understanding of membrane-bound desaturases is based on mutant studies, biochemical topology analysis, and the comparison of related enzymes with divergent functionality. Because ...
Lee Yong Joo - - 2007
In Saccharomyces cerevisiae, the initial reaction of the tricarboxylic acid cycle is catalyzed by the mitochondrial citrate synthase Cit1. The function of Cit1 has previously been studied mainly in terms of acetate utilization and metabolon construction. Here, we report the relationship between the function of Cit1 and apoptosis. Yeast cells ...
Walter Jens - - 2007
The dlt operon of Gram-positive bacteria encodes proteins required for the incorporation of D-alanine esters into cell wall-associated teichoic acids (TA). D-alanylation of TA has been shown to be important for acid tolerance, resistance to antimicrobial peptides, adhesion, biofilm formation, and virulence of a variety of pathogenic organisms. The aim ...
Roy Sébastien - - 2007
We have taken advantage of the intrinsic fluorescence properties of chitosanases to rapidly and quantitatively evaluate the protective effect of chitosan against thermal denaturation of chitosanases. The studies were done using wild type chitosanases N174 produced by Streptomyces sp. N174 and SCO produced by Streptomyces coelicolor A3(2). In addition, two ...
Neu Daniel - - 2007
Amidase 1 (AMI1), a specific indole-3-acetamide amidohydrolase, is an Arabidopsis thaliana amidase signature enzyme that catalyzes the synthesis of indole-3-acetic acid from indole-3-acetamide. Amidase signature family members catalyze a diverse range of enzymatic reactions and are found widespread in nature, for instance in bacteria, mammals, and plants. At the protein ...
Begic Sanela - - 2007
Serratia marcescens is a nosocomial bacterium with natural resistance to a broad spectrum of antibiotics, making treatment challenging. One factor contributing to this natural antibiotic resistance is reduced outer membrane permeability, controlled in part by OmpF and OmpC porin proteins. To investigate the direct role of these porins in the ...
Delker Carolin - - 2007
Jasmonic acid (JA) is an important regulator of plant development and stress responses. Several enzymes involved in the biosynthesis of JA from alpha-linolenic acid have been characterized. The final biosynthesis steps are the beta-oxidation of 12-oxo-phytoenoic acid. We analyzed JA biosynthesis in the Arabidopsis mutants pex6, affected in peroxisome biogenesis, ...
Butler Avigdor - - 2007
Acid sphingomyelinase knockout mice are a model of the inherited human disorder types A and B Niemann-Pick disease. Herein, we show that heterozygous (ASMKO(+/-)) mice have two distinct sperm populations resembling those found in normal and mutant animals, respectively, and that these two populations could be distinguished by their morphology, ...
Chen Shawn - - 2007
We have previously described methodology that makes it possible to genetically encode a wide array of unnatural amino acids in both prokaryotic and eukaryotic organisms. Here, we report the systematic optimization of a Saccharomyces cerevisiae expression system for the production of mutant proteins containing unnatural amino acids. Modifications include significant ...
Shibata Hiroko - - 2007
We have previously produced two bioactive lysine-deficient mutants of TNF-alpha (mutTNF-K90R,-K90P) and found that these mutants have bioactivity superior to wild-type TNF (wtTNF). Because these mutants contained same amino acid except for amino acid 90, it is unclear which amino acid residue is optimal for showing bioactivity. We speculated that ...
Gregori Christa - - 2007
Exposure of the yeast Saccharomyces cerevisiae to weak organic acids such as the food preservatives sorbate, benzoate and propionate leads to the pronounced induction of the plasma membrane ATP-binding cassette (ABC) transporter, Pdr12p. This protein mediates efflux of weak acid anions, which is essential for stress adaptation. Recently, we identified ...
Schmidt Roberto - - 2007
The development of seeds depends on the import of carbohydrates and amino acids supplied by the maternal tissue via the phloem. Several amino acid transporters have been reported to be expressed during seed and silique development in Arabidopsis thaliana (L.) Heynh. Here we show that mutants lacking the high affinity ...
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