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Results 251 - 300 of 1855
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Salcedo Ernesto - - 2009
The molecular mechanisms that regulate invertebrate visual pigment absorption are poorly understood. Through sequence analysis and functional investigation of vertebrate visual pigments, numerous amino acid substitutions important for this adaptive process have been identified. Here we describe a serine/alanine (S/A) substitution in long wavelength-absorbing Drosophila visual pigments that occurs at ...
Boudehri Karima - - 2009
BACKGROUND: Acidity is an essential component of the organoleptic quality of fleshy fruits. However, in these fruits, the physiological and molecular mechanisms that control fruit acidity remain unclear. In peach the D locus controls fruit acidity; low-acidity is determined by the dominant allele. Using a peach progeny of 208 F2 ...
Clarke Shannon M - - 2009
* The cpr5-1 Arabidopsis thaliana mutant exhibits constitutive activation of salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signalling pathways and displays enhanced tolerance of heat stress (HS). * cpr5-1 crossed with jar1-1 (a JA-amino acid synthetase) was compromised in basal thermotolerance, as were the mutants opr3 (mutated in ...
Vicente Cláudia M - - 2009
Polyenes represent a major class of antifungal agents characterised by the presence of a series of conjugated double bonds in their planar hydroxylated macrolide ring structure. Despite their general interest, very little is known about the factors that modulate their biosynthesis. Among these factors, we have recently discovered a new ...
Gong Wei - - 2009
BACKGROUND: Antibacterial activity is a novel function of high-mobility group box 1 (HMGB1). However, the functional site for this new effect is presently unknown. METHODS AND RESULTS: In this study, recombinant human HMGB1 A box and B box (rHMGB1 A box, rHMGB1 B box), recombinant human HMGB1 (rHMGB1) and the ...
Fleet Christine M - - 2009
To respond to physical signals and endogenous hormones, plants use specific signal transduction pathways. We and others have previously shown that second messenger inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)] is used in abscisic acid (ABA) signaling, and that some mutants with altered Ins(1,4,5)P(3) have altered responses to ABA. Specifically, mutants defective in the ...
Gurvitz Aner - - 2009
Our recognition of the mitochondria as being important sites of fatty acid biosynthesis is continuously unfolding, especially in light of new data becoming available on compromised fatty acid synthase type 2 (FASII) in mammals. For example, perturbed regulation of murine 17beta-HSD8 encoding a component of the mitochondrial FASII enzyme 3-oxoacyl-thioester ...
Jouhten Paula - - 2009
The filamentous fungus Trichoderma reesei is an important host organism for industrial enzyme production. It is adapted to nutrient poor environments where it is capable of producing large amounts of hydrolytic enzymes. In its natural environment T. reesei is expected to benefit from high energy yield from utilization of respirative ...
Botosso Viviane F - - 2009
Human respiratory syncytial virus (HRSV) is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly ...
Liu Yinggao Y Department of Biology, Hong Kong Baptist University, Hong Kong, - - 2009
Nitric oxide (NO) has been reported to be involved in breaking seed dormancy but its mechanism of action is unclear. Here, we report that a rapid accumulation of NO induced an equally rapid decrease of abscisic acid (ABA) that is required for this action in Arabidopsis. Results of quantitative real-time ...
Trusov Yuri - - 2009
Heterotrimeric G proteins are involved in the defense response against necrotrophic fungi in Arabidopsis. In order to elucidate the resistance mechanisms involving heterotrimeric G proteins, we analyzed the effects of the Gβ (subunit deficiency in the mutant agb1-2 on pathogenesis-related gene expression, as well as the genetic interaction between agb1-2 and a ...
Fiorini Emma - - 2008
Interactions between Notch1 receptors on lymphoid progenitors and Delta-like 4 (DL4) ligands on cortical thymic epithelial cells (cTEC) are essential for T cell lineage commitment, expansion, and maturation in the thymus. Using a novel mAb against DL4, we show that DL4 levels on cTEC are very high in the fetal ...
Rout Manoj Kumar - - 2009
Folding, in-vivo, starts from a denatured state and thus the nature of the denatured state would play an important role in directing the folding of a protein. We report here NMR characterization of the acid-denatured state of a mutant of HIV-1 protease, designed to prevent autolysis (Q7K, L33I, L63I) and ...
Ikrar Taruna - - 2009
The effect of the electrical charge or the size of the amino acid residue at the pore center of a slowly activation component of the delayed rectifier potassium channel: KCNQ1 was studied. K(+) currents were measured after transfection of one of four KCNQ1 mutants: substituting Isoleucine with Lysine, Glutamate, Valine ...
Dalebroux Zachary D - - 2009
During its life cycle, Legionella pneumophila alternates between a replicative and a transmissive state. To determine their contributions to L. pneumophila differentiation, the two ppGpp synthetases, RelA and SpoT, were disrupted. Synthesis of ppGpp was required for transmission, as relA spoT mutants were killed during entry to and exit from ...
Urano Kaoru - - 2009
Drought is the major environmental threat to agricultural production and distribution worldwide. Adaptation by plants to dehydration stress is a complex biological process that involves global changes in gene expression and metabolite composition. Here, using one type of functional genomics analysis, metabolomics, we characterized the metabolic phenotypes of Arabidopsis wild-type ...
Sandmann Gerhard - - 2008
The Neurospora crassa mutant YLO exhibits a yellow phenotype instead of the red-orange pigmentation of the wild type. Recently, it was shown that the mutant YLO is defective in a specific aldehyde dehydrogenase which catalyses the last step of carotenogenesis to the formation of neurosporaxanthin [Estrada, A.F., Youssar, L., Scherzinger, ...
Mène-Saffrané Laurent - - 2009
In higher plants such as Arabidopsis thaliana, omega-3 trienoic fatty acids (TFAs), represented mainly by alpha-linolenic acid, serve as precursors of jasmonic acid (JA), a potent lipid signal molecule essential for defense. The JA-independent roles of TFAs were investigated by comparing the TFA- and JA-deficient fatty acid desaturase triple mutant ...
Yu Hong - - 2009
To facilitate the easier production of D-amino acids using N-carbamyl-D-amino acid amidohydrolase (DCase) in an immobilized form, we improved the enzymatic thermostability of highly soluble DCase-M3 of Ralstonia pickettii using directed mutagenesis. Six novel mutation sites were identified in this study, apart from several thermostability-related amino acid sites reported previously. ...
Chen Yi-Pei - - 2008
The filamentous fungus Monascus pilosus was genetically transformed with a reporter plasmid, pMS-1.5hp, by aurintricarboxylic acid (ATA) treatment to obtain an efficient red-pigment producing mutant. The transformation efficiency of Monascus pilosus was higher with the ATA-treatment than with either a non-restriction-enzyme-mediated integration (REMI) or a REMI method. This valid and ...
van Alphen Lieke B - - 2008
Flagellin of Campylobacter jejuni is extensively modified with (derivatives of) pseudaminic acid. The flagellar glycosylation locus contains several genes with homopolymeric G-tracts prone to slipped-strand mispairing, some of which belong to the maf gene family. We investigated the function of the putative phase-variable maf4 gene of C. jejuni strain 108. ...
Yeom Soo-Jin - - 2008
Nitrilase from Rhodococcus rhodochrous ATCC 33278 hydrolyses both aliphatic and aromatic nitriles. Replacing Tyr-142 in the wild-type enzyme with the aromatic amino acid phenylalanine did not alter specificity for either substrate. However, the mutants containing non-polar aliphatic amino acids (alanine, valine and leucine) at position 142 were specific only for ...
Cavatorta J R - - 2008
Explicit evaluation of the accuracy and power of maximum likelihood and Bayesian methods for detecting site-specific positive Darwinian selection presents a challenge because selective consequences of single amino acid changes are generally unknown. We exploited extensive molecular and functional characterization of amino acid substitutions in the plant gene eIF4E to ...
Lasseur Bertrand - - 2009
Fructosyltransferases (FTs) synthesize fructans, fructose polymers accumulating in economically important cool-season grasses and cereals. FTs might be crucial for plant survival under stress conditions in species in which fructans represent the major form of reserve carbohydrate, such as perennial ryegrass (Lolium perenne). Two FT types can be distinguished: those using ...
Brown Roslyn N - - 2008
The opportunistic bacterial pathogen Vibrio vulnificus causes severe wound infection and fatal septicemia. We used alkaline phosphatase insertion mutagenesis in a clinical isolate of V. vulnificus to find genes necessary for virulence, and we identified fadR, which encodes a regulator of fatty acid metabolism. The fadR::mini-Tn5Km2phoA mutant was highly attenuated ...
Fujiwara Ryoichi - - 2009
Human UDP-glucuronosyltransferase (UGT)1A9 is one of the major isoforms in liver and extrahepatic tissues, catalyzing the glucuronidation of a variety of drugs, dietary constituents, steroids, fatty acids, and bile acids. UGT1A9 shows high amino acid homology with UGT1A7, UGT1A8, and UGT1A10 with overlapping substrate specificity. However, the affinities for substrates ...
Jahan Md Sarwar - - 2008
We investigated the role of glutathione (GSH) in stomatal movements using a GSH deficient mutant, chlorinal-1 (ch1-1). Guard cells of ch1-1 mutants accumulated less GSH than wild types did. Light induced stomatal opening in ch1-1 and wild-type plants. Abscisic acid (ABA) induced stomatal closure in ch1-1 mutants more than wild ...
Stoddart Leigh A - - 2008
FFA2 and FFA3 are closely related G protein-coupled receptors that bind and respond to short chain fatty acids. (FFA2 and FFA3 are the provisional International Union of Pharmacology designations for the receptors previously called GPR43 and GPR41, respectively.) Sequence comparisons between these two receptors and alignments with the related G ...
López-Martín Carmen - - 2008
Sitamaquine (WR6026), an 8-aminoquinoline derivative, is a new antileishmanial oral drug. As a lipophilic weak base, it rapidly accumulates in acidic compartments, represented mainly by acidocalcisomes. In this work, we show that the antileishmanial action of sitamaquine is unrelated to its level of accumulation in these acidic vesicles. We have ...
Estrada Alejandro F - - 2008
Neurosporaxanthin, beta-apo-4'-carotenoic acid (C35), represents the end-product of the carotenoid pathway in Neurospora crassa. It is supposed to be synthesized in three steps catalyzed by sequential AL-2, CAO-2 and YLO-1 activities: (i) cyclization of 3,4-didehydrolycopene (C40); (ii) cleavage of torulene into beta-apo-4'-carotenal (C35); and finally (iii) oxidation of beta-apo-4'-carotenal. However, ...
Wr??bel Maria - - 2009
The interdependence of the sulfane sulfur metabolism and sulfur amino acid metabolism was studied in the fungus Aspergillus nidulans wild type strain and in mutants impaired in genes encoding enzymes involved in the synthesis of cysteine (a precursor of sulfane sulfur) or in regulatory genes of the sulfur metabolite repression ...
Schonauer Melissa S - - 2008
Distinct metabolic pathways can intersect in ways that allow hierarchical or reciprocal regulation. In a screen of respiration-deficient Saccharomyces cerevisiae gene deletion strains for defects in mitochondrial RNA processing, we found that lack of any enzyme in the mitochondrial fatty acid type II biosynthetic pathway (FAS II) led to inefficient ...
Kurdi Peter - - 2009
Acid-sensitive mutants of Pediococcus acidilactici BCC 9545, a starter culture of the Thai fermented pork sausage nham, were isolated as spontaneous neomycin resistant mutants. The mutants generally produced less acid and acidified the culture media less than the parent strain in a 72 h culturing period. Interestingly, the ATPase activities ...
de las Nieves Peltzer Maria - - 2008
Some Sinorhizobium meliloti mutants in genes involved in isoleucine, valine, and leucine biosynthesis were previously described as being unable to induce nodule formation on host plants. Here, we present a reappraisal of the interconnection between the branched-chain amino acid biosynthesis pathway and the nodulation process in S. meliloti. We characterized ...
Lehner Arnaud - - 2008
Oxalic acid is thought to be a key factor of the early pathogenic stage in a wide range of necrotrophic fungi. We have recently published that oxalic acid induces Programmed Cell Death (PCD) in Arabidopsis thaliana cells. This cell death results from an early anionic efflux which is a prerequisite ...
Thiaville Michelle M - - 2008
It is unclear whether Mediator complex in yeast is necessary for all RNA polymerase II (Pol II) transcription or if it is limited to genes activated by environmental stress. In mammals, amino acid limitation induces SNAT2 transcription through ATF4 binding at an amino acid response element. ATF4 is the functional ...
Yaeno Takashi - - 2008
Salicylic acid (SA) is a primary factor responsible for exerting diverse immune responses in plants and is synthesized in response to attack by a wide range of pathogens. The Arabidopsis (Arabidopsis thaliana) sid2 mutant is defective in a SA biosynthetic pathway involving ISOCHORISMATE SYNTHASE1 (ICS1) and consequently contains reduced levels ...
Zolman Bethany K - - 2008
Genetic evidence suggests that indole-3-butyric acid (IBA) is converted to the active auxin indole-3-acetic acid (IAA) by removal of two side-chain methylene units in a process similar to fatty acid beta-oxidation. Previous studies implicate peroxisomes as the site of IBA metabolism, although the enzymes that act in this process are ...
Konsavage Wesley M WM - - 2008
The catalytic domain of all retroviral integrases contains an Asp,Asp-35-Glu (D,D-35-E) motif with precisely 35 amino acids between the second aspartate and the glutamate. We have now made several mutations designed to alter the length or flexibility of a mobile loop within this 35-amino-acid spacer region in full-length Rous sarcoma ...
Mikheenko I P - - 2008
Wild-type Desulfovibrio fructosivorans and three hydrogenase-negative mutants reduced Pd(II) to Pd(0). The location of Pd(0) nanoparticles on the cytoplasmic membrane of the mutant retaining only cytoplasmic membrane-bound hydrogenase was strong evidence for the role of hydrogenases in Pd(0) deposition. Hydrogenase activity was retained at acidic pH, shown previously to favor ...
Singh Vineet K - - 2008
Staphylococcus aureus is a major community and nosocomial pathogen. Its ability to withstand multiple stress conditions and quickly develop resistance to antibiotics complicates the control of staphylococcal infections. Adaptation to lower temperatures is a key for the survival of bacterial species outside the host. Branched-chain alpha-keto acid dehydrogenase (BKD) is ...
Meleigy Samir A - - 2009
Gibberellic acid (GA) production from milk permeate was studied by 28 mutants of Fusarium moniliforme, among which mutant gamma-14 was selected as the best producer. Experiments were carried out in shaker flasks and fermentative process was analyzed with free and immobilized cells. Immobilization of mutant gamma-14 cells onto loofa sponge ...
Gupta Ankur - - 2008
Rice alpha-oxygenase (RalphaO) catalyzes the insertion of O2 into the Calpha-H bond of various fatty acids. The mechanism is thought to involve a tyrosyl radical as the oxidant on the basis of comparisons to the structurally homologous cyclooxygenase enzymes. Kinetic and spectroscopic results presented here for the wild-type RalphaO and ...
Briers Yves - - 2008
Gp181 (2237 amino acids) of Pseudomonas aeruginosa bacteriophage phiKZ (Myoviridae) is a structural virion protein, which bears a peptidoglycan hydrolase domain near its C-terminus. This protein is supposed to degrade the peptidoglycan locally during the infection process. Nine deletional mutants allowed delineation of the peptidoglycan hydrolase domain between amino acids ...
Morizumi Takefumi - - 2009
Rhodopsin is one of the members of the G protein-coupled receptor family that can catalyze a GDP-GTP exchange reaction on the retinal G protein transducin (Gt) upon photon absorption. There are at least two intermediate states, meta-Ib and meta-II, which exhibit direct interaction with Gt. Meta-Ib binds to GDP-bound Gt, ...
Liu Yi-han - - 2008
This paper provided further understanding of the relationships between acid resistance and structural features of different mutants in Bacillus licheniformis alpha amylase (BLA) due to the changes of two crucial positions Leu134 and Ser320. In order to investigate effect of the two positions on the acid stability, we described the ...
Koszelak-Rosenblum Mary - - 2008
Pathogen-inducible oxygenase (PIOX) oxygenates fatty acids into 2R-hydroperoxides. PIOX belongs to the fatty acid alpha-dioxygenase family, which exhibits homology to cyclooxygenase enzymes (COX-1 and COX-2). Although these enzymes share common catalytic features, including the use of a tyrosine radical during catalysis, little is known about other residues involved in the ...
Chen Ming - - 2008
Sphingolipids are structural components of endomembranes and function through their metabolites as bioactive regulators of cellular processes such as programmed cell death. A characteristic feature of plant sphingolipids is their high content of trihydroxy long-chain bases (LCBs) that are produced by the LCB C-4 hydroxylase. To determine the functional significance ...
Tokunaga Hiroko - - 2008
Nucleoside diphosphate kinase from Halomonas sp. 593 (HaNDK) exhibits halophilic characteristics. Residues 134 and 135 in the carboxy-terminal region of HaNDK are Glu-Glu, while those of its homologous counterpart of non-halophilic Pseudomonas NDK (PaNDK) are Ala-Ala. The double mutation, E134A-E135A, in HaNDK results in the loss of the halophilic characteristics, ...
Wilding Timothy J - - 2008
RNA editing at the Q/R site in the GluR5 and GluR6 subunits of neuronal kainate receptors regulates channel inhibition by lipid-derived modulators including the cis-unsaturated fatty acids arachidonic acid and docosahexaenoic acid. Kainate receptor channels in which all of the subunits are in the edited (R) form exhibit strong inhibition ...
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