| a lysr-type transcriptional regulator in burkholderia cenocepacia influences colony morphology and virulence. | burkholderia cenocepacia strain k56-2 typically has rough colony morphology on agar medium; however, shiny colony variants (shv) can appear spontaneously. these shv all had a minimum of 50% reduction in biomass formation and were generally avirulent in an alfalfa seedling infection model. three shv-k56-2 s15, k56-2 s76, and k56-2 s86-were analyzed for virulence in a chronic agar bead model of respiratory infection and, although all shv were able to establish chronic infection, they produced sign ... | 2008 | 17967860 |
| novel hexamerization motif is discovered in a conserved cytoplasmic protein from salmonella typhimurium. | the cytoplasmic protein stm3548 of unknown function obtained from a strain of salmonella typhimurium was determined by x-ray crystallography at a resolution of 2.25 a. the asymmetric unit contains a hexamer of structurally identical monomers. the monomer is a globular domain with a long beta-hairpin protrusion that distinguishes this structure. this beta-hairpin occupies a central position in the hexamer, and its residues participate in the majority of interactions between subunits of the hexame ... | 2007 | 17968677 |
| identification of differentially expressed small non-coding rnas in the legume endosymbiont sinorhizobium meliloti by comparative genomics. | bacterial small non-coding rnas (srnas) are being recognized as novel widespread regulators of gene expression in response to environmental signals. here, we present the first search for srna-encoding genes in the nitrogen-fixing endosymbiont sinorhizobium meliloti, performed by a genome-wide computational analysis of its intergenic regions. comparative sequence data from eight related alpha-proteobacteria were obtained, and the interspecies pairwise alignments were scored with the programs eqrn ... | 2007 | 17971083 |
| identification, structure and mode of action of a new regulator of the helicobacter pylori hp0525 atpase. | helicobacter pylori is one of the world's most successful human pathogens causing gastric ulcers and cancers. a key virulence factor of h. pylori is the cag pathogenicity island, which encodes a type iv secretion system. hp0525 is an essential component of the cag system and acts as an inner membrane associated atpase. hp0525 forms double hexameric ring structures, with the c-terminal domains (ctds) forming a closed ring and the n-terminal domains (ntds) forming a dynamic, open ring. here, the c ... | 2007 | 17972918 |
| the virb5 protein localizes to the t-pilus tips in agrobacterium tumefaciens. | the agrobacterium tumefaciens virb/d4 type iv secretion system (t4ss) mediates the transfer of single-stranded dna and protein virulence factors into plant cells, and also determines the assembly of the t-pilus, which is believed to play a role in host recognition. the t-pilus is composed of the major component virb2 and the minor component virb5. using immuno-electron microscopy we detected the major component virb2 along the entire length of detached t-pili, but not on cell-bound t-pili or on ... | 2007 | 17975085 |
| structural characterizations of lipids a by ms/ms of doubly charged ions on a hybrid linear ion trap/orbitrap mass spectrometer. | here, a new 'one pot' and fast approach is described, based on electrospray ionization (esi) of negative ions by using a hybrid linear ion trap/orbitrap mass spectrometer (ltq/orbitrap) for ms and ms/ms analysis. by this method the distribution of the primary and secondary acyl residues of the intact lipid a is inferred by analysis of the esi spectra measured in positive and negative mode. the analysis of these data allows an unequivocal assignment of the fatty acid distribution. this methodolog ... | 2008 | 17975853 |
| phosphatidylcholine synthesis is required for optimal function of legionella pneumophila virulence determinants. | the function of phosphatidylcholine (pc) in the bacterial cell envelope remains cryptic. we show here that productive interaction of the respiratory pathogen legionella pneumophila with host cells requires bacterial pc. synthesis of the lipid in l. pneumophila was shown to occur via either phospholipid n-methyltransferase (pmta) or phosphatidylcholine synthase (pcsa), but the latter pathway was demonstrated to be of predominant importance. loss of pc from the cell envelope caused lowered yields ... | 2008 | 17979985 |
| phosphatidylcholine synthesis is required for optimal function of legionella pneumophila virulence determinants. | the function of phosphatidylcholine (pc) in the bacterial cell envelope remains cryptic. we show here that productive interaction of the respiratory pathogen legionella pneumophila with host cells requires bacterial pc. synthesis of the lipid in l. pneumophila was shown to occur via either phospholipid n-methyltransferase (pmta) or phosphatidylcholine synthase (pcsa), but the latter pathway was demonstrated to be of predominant importance. loss of pc from the cell envelope caused lowered yields ... | 2008 | 17979985 |
| transient expression of hpv16 e7 peptide (aa 44-60) and hpv16 l2 peptide (aa 108-120) on chimeric potyvirus-like particles using potato virus x-based vector. | the optimized expression of recombinant potato virus a coat protein (acp) carrying two different epitopes from human papillomavirus type 16 (hpv16) was developed. epitope derived from minor capsid protein l2 was expressed as n-terminal fusion with acp while an epitope derived from e7 oncoprotein was fused to its c-terminus. the construct was cloned into potato x potexvirus (pvx) based vector and transiently expressed in plants using agrobacterium tumefaciens mediated inoculation. to increase the ... | 2008 | 17980618 |
| agrobacterium tumefaciens c58 uses actr and fnrn to control nirk and nor expression. | agrobacterium tumefaciens can grow anaerobically via denitrification. to learn more about how cells regulate production of nitrite and nitric oxide, experiments were carried out to identify proteins involved in regulating expression and activity of nitrite and nitric oxide reductase. transcription of nnrr, required for expression of these two reductases, was found to be under control of fnrn. insertional inactivation of the response regulator actr significantly reduced nirk expression and nir ac ... | 2008 | 17981975 |
| a set of modular binary vectors for transformation of cereals. | genetic transformation of crop plants offers the possibility of testing hypotheses about the function of individual genes as well as the exploitation of transgenes for targeted trait improvement. however, in most cereals, this option has long been compromised by tedious and low-efficiency transformation protocols, as well as by the lack of versatile vector systems. after having adopted and further improved the protocols for agrobacterium-mediated stable transformation of barley (hordeum vulgare) ... | 2007 | 17981986 |
| trehalose-6-phosphate synthase/phosphatase regulates cell shape and plant architecture in arabidopsis. | the vacuole occupies most of the volume of plant cells; thus, the tonoplast marker delta-tonoplast intrinsic protein-green fluorescent protein delineates cell shape, for example, in epidermis. this permits rapid identification of mutants. using this strategy, we identified the cell shape phenotype-1 (csp-1) mutant in arabidopsis thaliana. beyond an absence of lobes in pavement cells, phenotypes included reduced trichome branching, altered leaf serration and stem branching, and increased stomatal ... | 2008 | 17981987 |
| glufosinate ammonium-induced pathogen inhibition and defense responses culminate in disease protection in bar-transgenic rice. | glufosinate ammonium diminished developments of rice (oryza sativa) blast and brown leaf spot in 35s:bar-transgenic rice. pre- and postinoculation treatments of this herbicide reduced disease development. glufosinate ammonium specifically impeded appressorium formation of the pathogens magnaporthe grisea and cochliobolus miyabeanus on hydrophobic surface and on transgenic rice. in contrast, conidial germination remained unaffected. glufosinate ammonium diminished mycelial growth of two pathogens ... | 2008 | 17981989 |
| in situ proteolysis for protein crystallization and structure determination. | we tested the general applicability of in situ proteolysis to form protein crystals suitable for structure determination by adding a protease (chymotrypsin or trypsin) digestion step to crystallization trials of 55 bacterial and 14 human proteins that had proven recalcitrant to our best efforts at crystallization or structure determination. this is a work in progress; so far we determined structures of 9 bacterial proteins and the human aminoimidazole ribonucleotide synthetase (airs) domain. | 2007 | 17982461 |
| protease activity, self interaction, and small interfering rna binding of the silencing suppressor p1b from cucumber vein yellowing ipomovirus. | the rna silencing pathway mediated by small interfering rnas (sirnas) plays an important antiviral role in eukaryotes. to counteract this defense barrier, a large number of plant viruses express proteins with rna silencing suppression activity. recently, it was reported that the ipomovirus cucumber vein yellowing virus (cvyv), which lacks the typical silencing suppressor of members of the family potyviridae, i.e., hcpro, has a duplicated p1 coding sequence and that the downstream p1 copy, named ... | 2008 | 17989179 |
| protease activity, self interaction, and small interfering rna binding of the silencing suppressor p1b from cucumber vein yellowing ipomovirus. | the rna silencing pathway mediated by small interfering rnas (sirnas) plays an important antiviral role in eukaryotes. to counteract this defense barrier, a large number of plant viruses express proteins with rna silencing suppression activity. recently, it was reported that the ipomovirus cucumber vein yellowing virus (cvyv), which lacks the typical silencing suppressor of members of the family potyviridae, i.e., hcpro, has a duplicated p1 coding sequence and that the downstream p1 copy, named ... | 2008 | 17989179 |
| overexpression of the apple mpnpr1 gene confers increased disease resistance in malus x domestica. | the npr1 gene plays a pivotal role in systemic acquired resistance in plants. its overexpression in arabidopsis and rice results in increased disease resistance and elevated expression of pathogenesis-related (pr) genes. an npr1 homolog, mpnpr1-1, was cloned from apple (malus x domestica) and overexpressed in two important apple cultivars, galaxy and m26. apple leaf pieces were transformed with the mpnpr1 cdna under the control of the inducible pin2 or constitutive cauliflower mosaic virus (camv ... | 2007 | 17990964 |
| identification of acyltransferases required for cutin biosynthesis and production of cutin with suberin-like monomers. | cutin and suberin are the two major lipid-based polymers of plants. cutin is the structural polymer of the epidermal cuticle, the waterproof layer covering primary aerial organs and which is often the structure first encountered by phytopathogens. suberin contributes to the control of diffusion of water and solutes across internal root tissues and in periderms. the enzymes responsible for assembly of the cutin polymer are largely unknown. we have identified two arabidopsis acyltransferases essen ... | 2007 | 17991776 |
| global genomic analysis of pseudomonas savastanoi pv. savastanoi plasmids. | pseudomonas savastanoi pv. savastanoi strains harbor native plasmids belonging to the ppt23a plasmid family (pfps) which are detected in all pathovars of the related species pseudomonas syringae examined and contribute to the ecological and pathogenic fitness of their host. however, there is a general lack of information about the gene content of p. savastanoi pv. savastanoi plasmids and their role in the interaction of this pathogen with olive plants. we designed a dna macroarray containing 135 ... | 2008 | 17993520 |
| global genomic analysis of pseudomonas savastanoi pv. savastanoi plasmids. | pseudomonas savastanoi pv. savastanoi strains harbor native plasmids belonging to the ppt23a plasmid family (pfps) which are detected in all pathovars of the related species pseudomonas syringae examined and contribute to the ecological and pathogenic fitness of their host. however, there is a general lack of information about the gene content of p. savastanoi pv. savastanoi plasmids and their role in the interaction of this pathogen with olive plants. we designed a dna macroarray containing 135 ... | 2008 | 17993520 |
| transcriptome profiling and functional analysis of agrobacterium tumefaciens reveals a general conserved response to acidic conditions (ph 5.5) and a complex acid-mediated signaling involved in agrobacterium-plant interactions. | agrobacterium tumefaciens transferred dna (t-dna) transfer requires that the virulence genes (vir regulon) on the tumor-inducing (ti) plasmid be induced by plant phenolic signals in an acidic environment. using transcriptome analysis, we found that these acidic conditions elicit two distinct responses: (i) a general and conserved response through which agrobacterium modulates gene expression patterns to adapt to environmental acidification and (ii) a highly specialized acid-mediated signaling re ... | 2008 | 17993523 |
| multiple phospholipid n-methyltransferases with distinct substrate specificities are encoded in bradyrhizobium japonicum. | phosphatidylcholine (pc) is the major phospholipid in eukaryotic membranes. in contrast, it is found in only a few prokaryotes including members of the family rhizobiaceae. in these bacteria, pc is required for pathogenic and symbiotic plant-microbe interactions, as shown for agrobacterium tumefaciens and bradyrhizobium japonicum. at least two different phospholipid n-methyltransferases (pmta and pmtx) have been postulated to convert phosphatidylethanolamine (pe) to pc in b. japonicum by three c ... | 2008 | 17993534 |
| massetolide a biosynthesis in pseudomonas fluorescens. | massetolide a is a cyclic lipopeptide (clp) antibiotic produced by various pseudomonas strains from diverse environments. cloning, sequencing, site-directed mutagenesis, and complementation showed that massetolide a biosynthesis in p. fluorescens ss101 is governed by three nonribosomal peptide synthetase (nrps) genes, designated massa, massb, and massc, spanning approximately 30 kb. prediction of the nature and configuration of the amino acids by in silico analysis of adenylation and condensatio ... | 2008 | 17993540 |
| massetolide a biosynthesis in pseudomonas fluorescens. | massetolide a is a cyclic lipopeptide (clp) antibiotic produced by various pseudomonas strains from diverse environments. cloning, sequencing, site-directed mutagenesis, and complementation showed that massetolide a biosynthesis in p. fluorescens ss101 is governed by three nonribosomal peptide synthetase (nrps) genes, designated massa, massb, and massc, spanning approximately 30 kb. prediction of the nature and configuration of the amino acids by in silico analysis of adenylation and condensatio ... | 2008 | 17993540 |
| a bifunctional locus (bio3-bio1) required for biotin biosynthesis in arabidopsis. | we identify here the arabidopsis (arabidopsis thaliana) gene encoding the third enzyme in the biotin biosynthetic pathway, dethiobiotin synthetase (bio3; at5g57600). this gene is positioned immediately upstream of bio1, which is known to be associated with the second reaction in the pathway. reverse genetic analysis demonstrates that bio3 insertion mutants have a similar phenotype to the bio1 and bio2 auxotrophs identified using forward genetic screens for arrested embryos rescued on enriched nu ... | 2008 | 17993549 |
| argonaute4 is required for resistance to pseudomonas syringae in arabidopsis. | here, we report the characterization of the arabidopsis thaliana ocp11 (for overexpressor of cationic peroxidase11) mutant, in which a beta-glucuronidase reporter gene under the control of the h(2)o(2)-responsive ep5c promoter is constitutively expressed. ocp11 plants show enhanced disease susceptibility to the virulent bacterium pseudomonas syringae pv tomato dc3000 (p.s.t. dc3000) and also to the avirulent p.s.t. dc3000 carrying the effector avrrpm1 gene. in addition, ocp11 plants are also com ... | 2007 | 17993621 |
| high-level transient production of a heterologous protein in plants by optimizing induction of a chemically inducible viral amplicon expression system. | we have demonstrated that the method of chemical induction using a chemically inducible viral amplicon expression system can be optimized to increase expression of a heterologous protein in plants. a cucumber mosaic virus inducible viral amplicon (cmviva) expression system was used to transiently produce a recombinant human blood protein, alpha-1-antitrypsin (aat), by co-infiltrating intact and detached nicotiana benthamiana leaves with two agrobacterium tumefaciens strains, one containing the c ... | 2007 | 17994759 |
| expression of the fluorescence markers dsred and gfp fused to a nuclear localization signal in the arbuscular mycorrhizal fungus glomus intraradices. | here, arbuscular mycorrhizal (am) fungi were monitored in vivo introducing the fluorescent reporters dsred and gfp (green fluorescent protein) in glomus intraradices using a biolistic approach and agrobacterium tumefaciens-mediated transformation. both reporter genes were fused to the nuclear localization signal of the aspergillus nidulans transcription factor stua to target fluorescence to nuclei. expression of dsred was driven by two glomus mosseae promoters highly expressed during early symbi ... | 2008 | 17995919 |
| sequence and functional analyses of haemophilus spp. genomic islands. | a major part of horizontal gene transfer that contributes to the diversification and adaptation of bacteria is facilitated by genomic islands. the evolution of these islands is poorly understood. some progress was made with the identification of a set of phylogenetically related genomic islands among the proteobacteria, recognized from the investigation of the evolutionary origins of a haemophilus influenzae antibiotic resistance island, namely icehin1056. more clarity comes from this comparativ ... | 2007 | 17996041 |
| variation of 16s-23s internally transcribed spacer sequence and intervening sequence in rdna among the three major agrobacterium species. | we analyzed 16s-23s internally transcribed spacer (its) and neighboring sequences among 37 strains belonging to the three major pathogenic agrobacterium species, in order to know variation in each species and to develop a simple discrimination method. number of its size variation was 9, 4, and 7 in agrobacterium tumefaciens, agrobacterium vitis, and agrobacterium rhizogenes, respectively. the its sequence of most strains in each species was distinguishable from that of the other two species. the ... | 2009 | 17997085 |
| separation of plant pathogens from different hosts and tissues by capillary electromigration techniques. | in this contribution capillary isoelectric focusing and capillary zone electrophoresis were applied for the separation and detection of different plant pathogens including pseudomonas syringae pv. syringae, p. syringae pv. lachrymans, pseudomonas savastanoi pv. fraxinus, p. savastanoi pv. olea, agrobacterium tumefaciens, a vitis, xanthomonas arboricola pv. juglandis, x. campestris pv. zinniae, and curtobacterium sp.. the uv detection and sensitive fluorescence detection of the native phytopathog ... | 2007 | 17997525 |
| a novel class of bacteria-induced small rnas in arabidopsis. | small rnas, including micrornas (mirnas) and small interfering rnas (sirnas), are essential regulatory molecules of many cellular processes. arabidopsis has at least three classes of endogenous sirnas--chromatin-associated sirnas, trans-acting sirnas (tasirnas), and natural antisense transcript (nat)-associated sirnas (nat-sirnas)--all 20-25 nucleotides (nt) in length. here, we identified a novel class of small rnas, long sirnas (lsirnas), which are 30-40 nt and share many common features with k ... | 2007 | 18003861 |
| the shoot meristem identity gene tfl1 is involved in flower development and trafficking to the protein storage vacuole. | plants are unique in their ability to store proteins in specialized protein storage vacuoles (psvs) within seeds and vegetative tissues. although plants use psv proteins during germination, before photosynthesis is fully functional, the roles of psvs in adult vegetative tissues are not understood. trafficking pathways to psvs and lytic vacuoles appear to be distinct. lytic vacuoles are analogous evolutionarily to yeast and mammalian lysosomes. however, it is unclear whether trafficking to psvs h ... | 2007 | 18003908 |
| foliar extracts from transgenic tomato plants expressing the structural polyprotein, p1-2a, and protease, 3c, from foot-and-mouth disease virus elicit a protective response in guinea pigs. | the expression of recombinant antigens in transgenic plants is increasingly used as an alternative method of producing experimental immunogens. in this report, we describe the production of transgenic tomato plants that express the structural polyprotein, p1-2a, and protease, 3c, from foot-and-mouth disease (fmdv). p1-2a3c was inserted into the plant binary vector, pbin438, and transformed into tomato plants using agrobacterium tumefaciens strain, gv3101. the presence of p1-2a3c was confirmed by ... | 2008 | 18006078 |
| purification, crystallization and preliminary x-ray crystallographic analysis of st1022, a putative member of the lrp/asnc family of transcriptional regulators isolated from sulfolobus tokodaii strain 7. | the lrp/asnc family of transcriptional regulators, also known as feast/famine transcriptional regulators, are widely distributed among bacteria and archaea. this family of proteins are likely to be involved in cellular metabolism, with exogenous amino acids functioning as effectors. here, the crystallization and preliminary x-ray diffraction analysis of st1022, a member of the lrp/asnc family of proteins, is reported with and without exogenous glutamine as the effector molecule. the crystals of ... | 2007 | 18007052 |
| theoretical study of molecular determinants involved in signal binding to the trar protein of agrobacterium tumefaciens. | n-acylated homoserine lactone (ahl) mediated cell-cell communication in bacteria is dependent on the recognition of the cognate signal by its receptor. this interaction allows the receptor-ligand complex to act as a transcriptional activator, controlling the expression of a range of bacterial phenotypes, including virulence factor expression and biofilm formation. one approach to determine the key features of signal- binding is to model the intermolecular interactions between the receptor and li ... | 2005 | 18007518 |
| a novel plant gene essential for meiosis is related to the human ctip and the yeast com1/sae2 gene. | obligatory homologous recombination (hr) is required for chiasma formation and chromosome segregation in meiosis i. meiotic hr is initiated by dna double-strand breaks (dsbs), generated by spo11, a homologue of the archaebacterial topoisomerase subunit top6a. in saccharomyces cerevisiae, rad50, mre11 and com1/sae2 are essential to process an intermediate of the cleavage reaction consisting of spo11 covalently linked to the 5' termini of dna. while rad50 and mre11 also confer genome stability to ... | 2007 | 18007598 |
| one-step cloning approach for construction of agroinfectious begomovirus clones. | most begomoviruses have a bipartite genome containing two circular ssdna segments (dna-a and dna-b). routine infectious clone construction relies upon cloning of the whole genome, which is then subcloned as a tandem one-and-half or two genome- (containing two replication origins) cassette into a vector prior to agro-inoculation. the construction of cassettes containing two replication origins is, however, a time-consuming process. here an improved method for rapid construction of agroinfectious ... | 2008 | 18022703 |
| a zn(ii)2cys6 dna binding protein regulates the sirodesmin pl biosynthetic gene cluster in leptosphaeria maculans. | a gene, sirz, encoding a zn(ii)(2)cys(6) dna binding protein is present in a cluster of genes responsible for the biosynthesis of the epipolythiodioxopiperazine (etp) toxin, sirodesmin pl in the ascomycete plant pathogen, leptosphaeria maculans. rna-mediated silencing of sirz gives rise to transformants that produce only residual amounts of sirodesmin pl and display a decrease in the transcription of several sirodesmin pl biosynthetic genes. this indicates that sirz is a major regulator of this ... | 2008 | 18023597 |
| a zn(ii)2cys6 dna binding protein regulates the sirodesmin pl biosynthetic gene cluster in leptosphaeria maculans. | a gene, sirz, encoding a zn(ii)(2)cys(6) dna binding protein is present in a cluster of genes responsible for the biosynthesis of the epipolythiodioxopiperazine (etp) toxin, sirodesmin pl in the ascomycete plant pathogen, leptosphaeria maculans. rna-mediated silencing of sirz gives rise to transformants that produce only residual amounts of sirodesmin pl and display a decrease in the transcription of several sirodesmin pl biosynthetic genes. this indicates that sirz is a major regulator of this ... | 2008 | 18023597 |
| eca3, a golgi-localized p2a-type atpase, plays a crucial role in manganese nutrition in arabidopsis. | calcium (ca) and manganese (mn) are essential nutrients required for normal plant growth and development, and transport processes play a key role in regulating their cellular levels. arabidopsis (arabidopsis thaliana) contains four p(2a)-type atpase genes, ateca1 to ateca4, which are expressed in all major organs of arabidopsis. to elucidate the physiological role of ateca2 and ateca3 in arabidopsis, several independent t-dna insertion mutant alleles were isolated. when grown on medium lacking m ... | 2008 | 18024560 |
| downregulation of cinnamoyl-coenzyme a reductase in poplar: multiple-level phenotyping reveals effects on cell wall polymer metabolism and structure. | cinnamoyl-coa reductase (ccr) catalyzes the penultimate step in monolignol biosynthesis. we show that downregulation of ccr in transgenic poplar (populus tremula x populus alba) was associated with up to 50% reduced lignin content and an orange-brown, often patchy, coloration of the outer xylem. thioacidolysis, nuclear magnetic resonance (nmr), immunocytochemistry of lignin epitopes, and oligolignol profiling indicated that lignin was relatively more reduced in syringyl than in guaiacyl units. t ... | 2007 | 18024569 |
| intracellular targeting of a hordeiviral membrane-spanning movement protein: sequence requirements and involvement of an unconventional mechanism. | the membrane-spanning protein tgbp3 is one of the three movement proteins (mps) of poa semilatent virus. tgbp3 is thought to direct other viral mps and genomic rna to peripheral bodies located in close proximity to plasmodesmata. we used the ectopic expression of green fluorescent protein-fused tgbp3 in epidermal cells of nicotiana benthamiana leaves to study the tgbp3 intracellular trafficking pathway. treatment with inhibitors was used to reveal that the targeting of tgbp3 to plasmodesmata doe ... | 2008 | 18032484 |
| intracellular targeting of a hordeiviral membrane-spanning movement protein: sequence requirements and involvement of an unconventional mechanism. | the membrane-spanning protein tgbp3 is one of the three movement proteins (mps) of poa semilatent virus. tgbp3 is thought to direct other viral mps and genomic rna to peripheral bodies located in close proximity to plasmodesmata. we used the ectopic expression of green fluorescent protein-fused tgbp3 in epidermal cells of nicotiana benthamiana leaves to study the tgbp3 intracellular trafficking pathway. treatment with inhibitors was used to reveal that the targeting of tgbp3 to plasmodesmata doe ... | 2008 | 18032484 |
| functional analysis of a novel abc transporter abc4 from magnaporthe grisea. | the atp-binding cassette (abc) superfamily of membrane transporters has been implicated to play a role in pathogenesis in various phytopathogenic fungi. in an insertional mutagenesis screen for pathogenicity mutants of magnaporthe grisea obtained via agrobacterium tumefaciens-mediated transformation (atmt), a novel gene belonging to the abc transporter family was identified. the gene abc4 was predicted to be 5045 bp in length coding for a protein of 1654 amino acids. the mutant did not form func ... | 2008 | 18034832 |
| molecular characterization of a functional type vi secretion system from a clinical isolate of aeromonas hydrophila. | our laboratory recently molecularly characterized the type ii secretion system (t2ss)-associated cytotoxic enterotoxin (act) and the t3ss-secreted aexu effector from a diarrheal isolate ssu of aeromonas hydrophila. the role of these toxin proteins in the pathogenesis of a. hydrophila infections was subsequently delineated in in vitro and in vivo models. in this study, we characterized the new type vi secretion system (t6ss) from isolate ssu of a. hydrophila and demonstrated its role in bacterial ... | 2008 | 18037263 |
| molecular characterization of a functional type vi secretion system from a clinical isolate of aeromonas hydrophila. | our laboratory recently molecularly characterized the type ii secretion system (t2ss)-associated cytotoxic enterotoxin (act) and the t3ss-secreted aexu effector from a diarrheal isolate ssu of aeromonas hydrophila. the role of these toxin proteins in the pathogenesis of a. hydrophila infections was subsequently delineated in in vitro and in vivo models. in this study, we characterized the new type vi secretion system (t6ss) from isolate ssu of a. hydrophila and demonstrated its role in bacterial ... | 2008 | 18037263 |
| implications of rewiring bacterial quorum sensing. | bacteria employ quorum sensing, a form of cell-cell communication, to sense changes in population density and regulate gene expression accordingly. this work investigated the rewiring of one quorum-sensing module, the lux circuit from the marine bacterium vibrio fischeri. steady-state experiments demonstrate that rewiring the network architecture of this module can yield graded, threshold, and bistable gene expression as predicted by a mathematical model. the experiments also show that the nativ ... | 2008 | 18039819 |
| implications of rewiring bacterial quorum sensing. | bacteria employ quorum sensing, a form of cell-cell communication, to sense changes in population density and regulate gene expression accordingly. this work investigated the rewiring of one quorum-sensing module, the lux circuit from the marine bacterium vibrio fischeri. steady-state experiments demonstrate that rewiring the network architecture of this module can yield graded, threshold, and bistable gene expression as predicted by a mathematical model. the experiments also show that the nativ ... | 2008 | 18039819 |
| the hypothetical protein atu4866 from agrobacterium tumefaciens adopts a streptavidin-like fold. | atu4866 is a 79-residue conserved hypothetical protein of unknown function from agrobacterium tumefaciens. protein sequence alignments show that it shares > or =60% sequence identity with 20 other hypothetical proteins of bacterial origin. however, the structures and functions of these proteins remain unknown so far. to gain insight into the function of this family of proteins, we have determined the structure of atu4866 as a target of a structural genomics project using solution nmr spectroscop ... | 2008 | 18042676 |
| cerk1, a lysm receptor kinase, is essential for chitin elicitor signaling in arabidopsis. | chitin is a major component of fungal cell walls and serves as a microbe-associated molecular pattern (mamp) for the detection of various potential pathogens in innate immune systems of both plants and animals. we recently showed that chitin elicitor-binding protein (cebip), plasma membrane glycoprotein with lysm motifs, functions as a cell surface receptor for chitin elicitor in rice. the predicted structure of cebip does not contain any intracellular domains, suggesting that an additional comp ... | 2007 | 18042724 |
| sequence-based analysis of pqbr103; a representative of a unique, transfer-proficient mega plasmid resident in the microbial community of sugar beet. | the plasmid pqbr103 was found within pseudomonas populations colonizing the leaf and root surfaces of sugar beet plants growing at wytham, oxfordshire, uk. at 425 kb it is the largest self-transmissible plasmid yet sequenced from the phytosphere. it is known to enhance the competitive fitness of its host, and parts of the plasmid are known to be actively transcribed in the plant environment. analysis of the complete sequence of this plasmid predicts a coding sequence (cds)-rich genome containing ... | 2007 | 18043644 |
| phylogenomics and signature proteins for the alpha proteobacteria and its main groups. | alpha proteobacteria are one of the largest and most extensively studied groups within bacteria. however, for these bacteria as a whole and for all of its major subgroups (viz. rhizobiales, rhodobacterales, rhodospirillales, rickettsiales, sphingomonadales and caulobacterales), very few or no distinctive molecular or biochemical characteristics are known. | 2007 | 18045498 |
| delayed leaf senescence induces extreme drought tolerance in a flowering plant. | drought, the most prominent threat to agricultural production worldwide, accelerates leaf senescence, leading to a decrease in canopy size, loss in photosynthesis and reduced yields. on the basis of the assumption that senescence is a type of cell death program that could be inappropriately activated during drought, we hypothesized that it may be possible to enhance drought tolerance by delaying drought-induced leaf senescence. we generated transgenic plants expressing an isopentenyltransferase ... | 2007 | 18048328 |
| increase of coq10 production level by the coexpression of decaprenyl diphosphate synthase and 1-deoxy-d-xylulose 5-phosphate synthase isolated from rhizobium radiobacter atcc 4718 in recombinant escherichia coli. | | 2007 | 18050926 |
| production of acyl-homoserine lactone quorum-sensing signals is widespread in gram-negative methylobacterium. | members of methylobacterium, referred as pink-pigmented facultative methylotrophic bacteria, are frequently associated with terrestrial and aquatic plants, tending to form aggregates on the phyllosphere. we report here that the production of autoinducer molecules involved in the cell-to-cell signaling process, which is known as quorum sensing, is common among methylobacterium species. several strains of methylobacterium were tested for their ability to produce n-acyl-homoserine lactone (ahl) sig ... | 2007 | 18051753 |
| processing of nuclear viroids in vivo: an interplay between rna conformations. | replication of viroids, small non-protein-coding plant pathogenic rnas, entails reiterative transcription of their incoming single-stranded circular genomes, to which the (+) polarity is arbitrarily assigned, cleavage of the oligomeric strands of one or both polarities to unit-length, and ligation to circular rnas. while cleavage in chloroplastic viroids (family avsunviroidae) is mediated by hammerhead ribozymes, where and how cleavage of oligomeric (+) rnas of nuclear viroids (family pospiviroi ... | 2007 | 18052530 |
| pyrroloquinoline quinone is a plant growth promotion factor produced by pseudomonas fluorescens b16. | pseudomonas fluorescens b16 is a plant growth-promoting rhizobacterium. to determine the factors involved in plant growth promotion by this organism, we mutagenized wild-type strain b16 using omegakm elements and isolated one mutant, k818, which is defective in plant growth promotion, in a rockwool culture system. a cosmid clone, pok40, which complements the mutant k818, was isolated from a genomic library of the parent strain. tn3-gusa mutagenesis of pok40 revealed that the genes responsible fo ... | 2008 | 18055583 |
| genetic and functional properties of the self-transmissible yersinia enterocolitica plasmid pye854, which mobilizes the virulence plasmid pyv. | yersinia strains frequently harbor plasmids, of which the virulence plasmid pyv, indigenous in pathogenic strains, has been thoroughly characterized during the last decades. yet, it has been unknown whether the nonconjugative pyv can be transferred by helper plasmids naturally occurring in this genus. we have isolated the conjugative plasmids pye854 (95.5 kb) and pye966 (70 kb) from a nonpathogenic and a pathogenic yersinia enterocolitica strain, respectively, and demonstrate that both plasmids ... | 2008 | 18055592 |
| genetic and functional properties of the self-transmissible yersinia enterocolitica plasmid pye854, which mobilizes the virulence plasmid pyv. | yersinia strains frequently harbor plasmids, of which the virulence plasmid pyv, indigenous in pathogenic strains, has been thoroughly characterized during the last decades. yet, it has been unknown whether the nonconjugative pyv can be transferred by helper plasmids naturally occurring in this genus. we have isolated the conjugative plasmids pye854 (95.5 kb) and pye966 (70 kb) from a nonpathogenic and a pathogenic yersinia enterocolitica strain, respectively, and demonstrate that both plasmids ... | 2008 | 18055592 |
| binding site determinants for the lysr-type transcriptional regulator pcaq in the legume endosymbiont sinorhizobium meliloti. | lysr-type transcriptional regulators represent one of the largest groups of prokaryotic regulators described to date. in the gram-negative legume endosymbiont sinorhizobium meliloti, enzymes involved in the protocatechuate branch of the beta-ketoadipate pathway are encoded within the pcadchgb operon, which is subject to regulation by the lysr-type protein pcaq. in this work, purified pcaq was shown to bind strongly (equilibrium dissociation constant, 0.54 nm) to a region at positions -78 to -45 ... | 2008 | 18055594 |
| prr3 is a vascular regulator of toc1 stability in the arabidopsis circadian clock. | the pseudoresponse regulators (prrs) participate in the progression of the circadian clock in arabidopsis thaliana. the founding member of the family, timing of cab expression1 (toc1), is an essential component of the transcriptional network that constitutes the core mechanism of the circadian oscillator. recent data suggest a role in circadian regulation for all five members of the prr family; however, the molecular function of toc1 or any other prrs remains unknown. in this work, we present ev ... | 2007 | 18055606 |
| the central cell plays a critical role in pollen tube guidance in arabidopsis. | the sperm cell of flowering plants cannot migrate unaided and must be transported by the pollen tube cell of the male gametophyte to achieve successful fertilization. long-distance pollen tube guidance is controlled by the seven-celled female gametophyte, the embryo sac. previous reports showed that the synergid cell of the embryo sac is essential for pollen tube guidance. here, we report the identification of a central cell guidance (ccg) mutant, which is defective in micropylar pollen tube gui ... | 2007 | 18055609 |
| pseudomonas syringae type iii effector avrrpt2 alters arabidopsis thaliana auxin physiology. | the pseudomonas syringae type iii effector avrrpt2 promotes bacterial virulence on arabidopsis thaliana plants lacking a functional rps2 gene (rps2 mutant plants). to investigate the mechanisms underlying the virulence activity of avrrpt2, we examined the phenotypes of transgenic a. thaliana rps2 seedlings constitutively expressing avrrpt2. these seedlings exhibited phenotypes reminiscent of a. thaliana mutants with altered auxin physiology, including longer primary roots, increased number of la ... | 2007 | 18056646 |
| recruitment of conjugative dna transfer substrate to agrobacterium type iv secretion apparatus. | bacterial type iv secretion system (t4ss) belongs to a growing class of evolutionarily conserved transporters that translocate dna and proteins into a wide variety of organisms including bacterial and eukaryotic cells. archetypal is the agrobacterium tumefaciens virb/d4 t4ss that transfers oncogenic t-dna to various eukaryotic cells, which is transferred as a nucleoprotein t-complex with vird2 as the pilot protein. as a derivative of plasmid conjugation systems, the virb/d4 t4ss can also transfe ... | 2007 | 18056647 |
| genetic transformation via somatic embryogenesis to establish herbicide-resistant opium poppy. | a reliable genetic transformation protocol via somatic embryogenesis has been developed for the production of fertile, herbicide-resistant opium poppy plants. transformation was mediated by agrobacterium tumefaciens using the pcambia3301 vector, which harbors the phosphinothricin acetyltransferase (pat) gene driven by a tandem repeat of the cauliflower mosaic virus (camv) 35s promoter and the beta-glucuronidase (gus) structural gene driven by a single copy of the camv 35s promoter between left- ... | 2008 | 18057938 |
| acc deaminase from plant growth-promoting bacteria affects crown gall development. | in addition to the well-known roles of indoleacetic acid and cytokinin in crown gall formation, the plant hormone ethylene also plays an important role in this process. many plant growth-promoting bacteria (pgpb) encode the enzyme 1-aminocyclopropane-1-carboxylate (acc) deaminase, which can degrade acc, the immediate precursor of ethylene in plants, to alpha-ketobutyrate and ammonia and thereby lower plant ethylene levels. to study the effect of acc deaminase on crown gall development, an acc de ... | 2007 | 18059561 |
| the agrobacterium tumefaciens dnak: atpase cycle, oligomeric state and chaperone properties. | dnak is a molecular chaperone that promotes cell survival during stress by preventing protein misfolding. the chaperone activity is regulated by nucleotide binding and hydrolysis events in the n-terminal atpase domain, which in turn mediate substrate binding and release in the c-terminal substrate binding domain. in this study we determined that atp hydrolysis was the rate limiting step in the atpase cycle of agrobacterium tumefaciens dnak (agt dnak); however the data suggested that agt dnak had ... | 2008 | 18061511 |
| a high-throughput agrobacterium-mediated transformation system for the grass model species brachypodium distachyon l. | in the ongoing process of developing brachypodium distachyon as a model plant for temperate cereals and forage grasses, we have developed a high-throughput agrobacterium-mediated transformation system for a diploid accession. embryogenic callus, derived from immature embryos of the accession bdr018, were transformed with agrobacterium tumefaciens strain agl1 carrying two t-dna plasmids, pdm805 and pwbv-ds-ubi-bar-ds. transient and stable transformation efficiencies were optimised by varying the ... | 2008 | 18064538 |
| pectin methyl esterase inhibits intrusive and symplastic cell growth in developing wood cells of populus. | wood cells, unlike most other cells in plants, grow by a unique combination of intrusive and symplastic growth. fibers grow in diameter by diffuse symplastic growth, but they elongate solely by intrusive apical growth penetrating the pectin-rich middle lamella that cements neighboring cells together. in contrast, vessel elements grow in diameter by a combination of intrusive and symplastic growth. we demonstrate that an abundant pectin methyl esterase (pme; ec 3.1.1.11) from wood-forming tissues ... | 2008 | 18065553 |
| firefly luciferase complementation imaging assay for protein-protein interactions in plants. | the development of sensitive and versatile techniques to detect protein-protein interactions in vivo is important for understanding protein functions. the previously described techniques, fluorescence resonance energy transfer and bimolecular fluorescence complementation, which are used widely for protein-protein interaction studies in plants, require extensive instrumentation. to facilitate protein-protein interaction studies in plants, we adopted the luciferase complementation imaging assay. t ... | 2008 | 18065554 |
| an arabidopsis purple acid phosphatase with phytase activity increases foliar ascorbate. | ascorbate (asa) is the most abundant antioxidant in plant cells and a cofactor for a large number of key enzymes. however, the mechanism of how asa levels are regulated in plant cells remains unknown. the arabidopsis (arabidopsis thaliana) activation-tagged mutant at23040 showed a pleiotropic phenotype, including ozone resistance, rapid growth, and leaves containing higher asa than wild-type plants. the phenotype was caused by activation of a purple acid phosphatase (pap) gene, atpap15, which co ... | 2008 | 18065557 |
| transgenic expression of a fungal endo-polygalacturonase increases plant resistance to pathogens and reduces auxin sensitivity. | polygalacturonases (pgs), enzymes that hydrolyze the homogalacturonan of the plant cell wall, are virulence factors of several phytopathogenic fungi and bacteria. on the other hand, pgs may activate defense responses by releasing oligogalacturonides (ogs) perceived by the plant cell as host-associated molecular patterns. tobacco (nicotiana tabacum) and arabidopsis (arabidopsis thaliana) plants expressing a fungal pg (pg plants) have a reduced content of homogalacturonan. here, we show that pg pl ... | 2008 | 18065558 |
| forest soil metagenome gene cluster involved in antifungal activity expression in escherichia coli. | using two forest soils, we previously constructed two fosmid libraries containing 113,700 members in total. the libraries were screened to select active antifungal clones using saccharomyces cerevisiae as a target fungus. one clone from the yuseong pine tree rhizosphere soil library, peaf66, showed s. cerevisiae growth inhibition. despite an intensive effort, active chemicals were not isolated. dna sequence analysis and transposon mutagenesis of peaf66 revealed 39 open reading frames (orfs) and ... | 2008 | 18065615 |
| forest soil metagenome gene cluster involved in antifungal activity expression in escherichia coli. | using two forest soils, we previously constructed two fosmid libraries containing 113,700 members in total. the libraries were screened to select active antifungal clones using saccharomyces cerevisiae as a target fungus. one clone from the yuseong pine tree rhizosphere soil library, peaf66, showed s. cerevisiae growth inhibition. despite an intensive effort, active chemicals were not isolated. dna sequence analysis and transposon mutagenesis of peaf66 revealed 39 open reading frames (orfs) and ... | 2008 | 18065615 |
| cytokinins act directly on lateral root founder cells to inhibit root initiation. | in arabidopsis thaliana, lateral roots are formed from root pericycle cells adjacent to the xylem poles. lateral root development is regulated antagonistically by the plant hormones auxin and cytokinin. while a great deal is known about how auxin promotes lateral root development, the mechanism of cytokinin repression is still unclear. elevating cytokinin levels was observed to disrupt lateral root initiation and the regular pattern of divisions that characterizes lateral root development in ara ... | 2007 | 18065686 |
| interaction between sgt1 and cytosolic/nuclear hsc70 chaperones regulates arabidopsis immune responses. | the conserved eukaryotic protein sgt1 (for suppressor of g2 allele of skp1) has characteristics of an hsp90 (for heat shock protein 90 kd) cochaperone and in plants regulates hormone responses and resistance gene-triggered immunity. we affinity-purified sgt1-interacting proteins from arabidopsis thaliana leaf extracts and identified by mass spectrometry cytosolic heat shock cognate 70 (hsc70) chaperones as the major stable sgt1 interactors. arabidopsis sgt1a and sgt1b proteins associate with hsc ... | 2007 | 18065690 |
| multiple ku orthologues mediate dna non-homologous end-joining in the free-living form and during chronic infection of sinorhizobium meliloti. | the bacterial non-homologous end-joining (nhej) apparatus is a two-component system that uses ku and ligd to repair dna double-strand breaks. although the reaction mechanism has been extensively studied, much less is known about the physiological role of bacterial nhej. recent studies suggest that nhej acts under conditions where dna replication is reduced or absent (such as in a spore or stationary phase). interestingly, genes encoding ku and ligd have been identified in a wide range of bacteri ... | 2008 | 18067541 |
| multiple ku orthologues mediate dna non-homologous end-joining in the free-living form and during chronic infection of sinorhizobium meliloti. | the bacterial non-homologous end-joining (nhej) apparatus is a two-component system that uses ku and ligd to repair dna double-strand breaks. although the reaction mechanism has been extensively studied, much less is known about the physiological role of bacterial nhej. recent studies suggest that nhej acts under conditions where dna replication is reduced or absent (such as in a spore or stationary phase). interestingly, genes encoding ku and ligd have been identified in a wide range of bacteri ... | 2008 | 18067541 |
| the legionella pneumophila icmsw complex interacts with multiple dot/icm effectors to facilitate type iv translocation. | many gram-negative pathogens use a type iv secretion system (t4ss) to deliver effector proteins into eukaryotic host cells. the fidelity of protein translocation depends on the efficient recognition of effector proteins by the t4ss. legionella pneumophila delivers a large number of effector proteins into eukaryotic cells using the dot/icm t4ss. how the dot/icm system is able to recognize and control the delivery of effectors is poorly understood. recent studies suggest that the icms and icmw pro ... | 2007 | 18069892 |
| modulation of bacterial type iii secretion system by a spermidine transporter dependent signaling pathway. | many gram-negative bacterial pathogens employ type iii secretion systems (t3ss) to inject effector proteins into host cells in infectious processes. | 2007 | 18074016 |
| core residue replacements cause coiled-coil orientation switching in vitro and in vivo: structure-function correlations for osmosensory transporter prop. | protein prop acts as an osmosensory transporter in diverse bacteria. c-terminal residues 468-497 of escherichia coli prop (propec) form a four-heptad homodimeric alpha-helical coiled coil. arg 488, at a core heptad a position, causes it to assume an antiparallel orientation. arg in the hydrophobic core of coiled coils is destabilizing, but arg 488 forms stabilizing interstrand salt bridges with asp 475 and asp 478. mutation r488i destabilizes the coiled coil and elevates the osmotic pressure at ... | 2008 | 18076193 |
| virb12 is a serological marker of brucella infection in experimental and natural hosts. | the brucella species type iv secretion system, encoded by the virb1-12 locus, is required for intracellular replication and persistent infection in vivo. the requirement of virb proteins for infection suggests that they are expressed in vivo and may therefore represent serological markers of infection. to test this idea, we purified recombinant virb1, virb5, virb11, and virb12 and tested for their recognition by antibodies in sera from experimentally infected mice and goats by using an indirect ... | 2008 | 18077620 |
| virb12 is a serological marker of brucella infection in experimental and natural hosts. | the brucella species type iv secretion system, encoded by the virb1-12 locus, is required for intracellular replication and persistent infection in vivo. the requirement of virb proteins for infection suggests that they are expressed in vivo and may therefore represent serological markers of infection. to test this idea, we purified recombinant virb1, virb5, virb11, and virb12 and tested for their recognition by antibodies in sera from experimentally infected mice and goats by using an indirect ... | 2008 | 18077620 |
| kalanchoe blossfeldiana plants expressing the arabidopsis etr1-1 allele show reduced ethylene sensitivity. | transgenic kalanchoe blossfeldiana poelln. with reduced ethylene sensitivity in flowers was obtained by agrobacterium tumefaciens-mediated transformation using the plasmid pbeo210 containing the mutant ethylene receptor gene etr1-1 from arabidopsis thaliana under the control of the flower-specific fbp1-promoter from petunia. three ethylene-resistent t0 lines, 300, 324 and 331, were selected and analyzed for postharvest-performance and morphological characteristics. line 324 was found to be infer ... | 2008 | 18080125 |
| in crystallo capture of a michaelis complex and product-binding modes of a bacterial phosphotriesterase. | the mechanism by which the binuclear metallophosphotriesterases (ptes, e.c. 3.1.8.1) catalyse substrate hydrolysis has been extensively studied. the mu-hydroxo bridge between the metal ions has been proposed to be the initiating nucleophile in the hydrolytic reaction. in contrast, analysis of some biomimetic systems has indicated that mu-hydroxo bridges are often not themselves nucleophiles, but act as general bases for freely exchangeable nucleophilic water molecules. herein, we present crystal ... | 2008 | 18082180 |
| escherichia coli cytosolic glycerophosphodiester phosphodiesterase (ugpq) requires mg2+, co2+, or mn2+ for its enzyme activity. | escherichia coli cytosolic glycerophosphodiester phosphodiesterase, ugpq, functions in the absence of other proteins encoded by the ugp operon and requires mg2+, mn2+, or co2+, in contrast to ca2+-dependent periplasmic glycerophosphodiester phosphodiesterase, glpq. ugpq has broad substrate specificity toward various glycerophosphodiesters, producing sn-glycerol-3-phosphate and the corresponding alcohols. ugpq accumulates under conditions of phosphate starvation, suggesting that it allows the uti ... | 2008 | 18083802 |
| escherichia coli cytosolic glycerophosphodiester phosphodiesterase (ugpq) requires mg2+, co2+, or mn2+ for its enzyme activity. | escherichia coli cytosolic glycerophosphodiester phosphodiesterase, ugpq, functions in the absence of other proteins encoded by the ugp operon and requires mg2+, mn2+, or co2+, in contrast to ca2+-dependent periplasmic glycerophosphodiester phosphodiesterase, glpq. ugpq has broad substrate specificity toward various glycerophosphodiesters, producing sn-glycerol-3-phosphate and the corresponding alcohols. ugpq accumulates under conditions of phosphate starvation, suggesting that it allows the uti ... | 2008 | 18083802 |
| a mutational analysis defines vibrio fischeri luxr binding sites. | vibrio fischeri quorum sensing involves the luxi and luxr proteins. the luxi protein generates the quorum-sensing signal n-3-oxohexanoyl-l-homoserine lactone (3oc6-hsl), and luxr is a signal-responsive transcriptional regulator which activates the luminescence (lux) genes and 17 other v. fischeri genes. for activation of the lux genes, luxr binds to a 20-base-pair inverted repeat, the lux box, which is centered 42.5 base pairs upstream of the transcriptional start of the lux operon. similar lux ... | 2008 | 18083819 |
| a mutational analysis defines vibrio fischeri luxr binding sites. | vibrio fischeri quorum sensing involves the luxi and luxr proteins. the luxi protein generates the quorum-sensing signal n-3-oxohexanoyl-l-homoserine lactone (3oc6-hsl), and luxr is a signal-responsive transcriptional regulator which activates the luminescence (lux) genes and 17 other v. fischeri genes. for activation of the lux genes, luxr binds to a 20-base-pair inverted repeat, the lux box, which is centered 42.5 base pairs upstream of the transcriptional start of the lux operon. similar lux ... | 2008 | 18083819 |
| the acyl-homoserine lactone-type quorum-sensing system modulates cell motility and virulence of erwinia chrysanthemi pv. zeae. | erwinia chrysanthemi pv. zeae is one of the erwinia chrysanthemi pathovars that infects on both dicotyledons and monocotyledons. however, little is known about the molecular basis and regulatory mechanisms of its virulence. by using a transposon mutagenesis approach, we cloned the genes coding for an e. chrysanthemi pv. zeae synthase of acyl-homoserine lactone (ahl) quorum-sensing signals (expi(ecz)) and a cognate response regulator (expr(ecz)). chromatography analysis showed that expi(ecz) enco ... | 2008 | 18083823 |
| the acyl-homoserine lactone-type quorum-sensing system modulates cell motility and virulence of erwinia chrysanthemi pv. zeae. | erwinia chrysanthemi pv. zeae is one of the erwinia chrysanthemi pathovars that infects on both dicotyledons and monocotyledons. however, little is known about the molecular basis and regulatory mechanisms of its virulence. by using a transposon mutagenesis approach, we cloned the genes coding for an e. chrysanthemi pv. zeae synthase of acyl-homoserine lactone (ahl) quorum-sensing signals (expi(ecz)) and a cognate response regulator (expr(ecz)). chromatography analysis showed that expi(ecz) enco ... | 2008 | 18083823 |
| structure of the minimized alpha/beta-hydrolase fold protein from thermus thermophilus hb8. | the gene encoding ttha1544 is a singleton found in the thermus thermophilus hb8 genome and encodes a 131-amino-acid protein. the crystal structure of ttha1544 has been determined at 2.0 a resolution by the single-wavelength anomalous dispersion method in order to elucidate its function. there are two molecules in the asymmetric unit. each molecule consists of four alpha-helices and six beta-strands, with the beta-strands composing a central beta-sheet. a structural homology search revealed that ... | 2007 | 18084077 |
| higher biomass accumulation by increasing phosphoribosylpyrophosphate synthetase activity in arabidopsis thaliana and nicotiana tabacum. | plants are able to produce all the organic compounds required for development and growth. as developmental processes and metabolic pathways use a common resource pool, the tight regulation of the distribution of metabolites between growth, production of defence compounds and storage products can be assumed. a transgenic approach was used to investigate the importance of supplying the key intermediate phosphoribosylpyrophosphate (prpp) for plant growth and biomass accumulation in the model plant ... | 2008 | 18086232 |
| identification of chromosomal alpha-proteobacterial small rnas by comparative genome analysis and detection in sinorhizobium meliloti strain 1021. | small untranslated rnas (srnas) seem to be far more abundant than previously believed. the number of srnas confirmed in e. coli through various approaches is above 70, with several hundred more srna candidate genes under biological validation. although the total number of srnas in any one species is still unclear, their importance in cellular processes has been established. however, unlike protein genes, no simple feature enables the prediction of the location of the corresponding sequences in g ... | 2007 | 18093320 |
| tobacco mosaic virus replicase-auxin/indole acetic acid protein interactions: reprogramming the auxin response pathway to enhance virus infection. | the replicase protein of tobacco mosaic virus (tmv) disrupts the localization and stability of interacting auxin/indole acetic acid (aux/iaa) proteins in arabidopsis, altering auxin-mediated gene regulation and promoting disease development (m. s. padmanabhan, s. p. goregaoker, s. golem, h. shiferaw, and j. n. culver, j. virol. 79:2549-2558, 2005). in this study, a similar replicase-aux/iaa interaction affecting disease development was identified in tomato. the ability of the tmv replicase to in ... | 2008 | 18094187 |
| tobacco mosaic virus replicase-auxin/indole acetic acid protein interactions: reprogramming the auxin response pathway to enhance virus infection. | the replicase protein of tobacco mosaic virus (tmv) disrupts the localization and stability of interacting auxin/indole acetic acid (aux/iaa) proteins in arabidopsis, altering auxin-mediated gene regulation and promoting disease development (m. s. padmanabhan, s. p. goregaoker, s. golem, h. shiferaw, and j. n. culver, j. virol. 79:2549-2558, 2005). in this study, a similar replicase-aux/iaa interaction affecting disease development was identified in tomato. the ability of the tmv replicase to in ... | 2008 | 18094187 |
| a systems biology approach identifies a r2r3 myb gene subfamily with distinct and overlapping functions in regulation of aliphatic glucosinolates. | glucosinolates are natural metabolites in the order brassicales that defend plants against both herbivores and pathogens and can attract specialized insects. knowledge about the genes controlling glucosinolate regulation is limited. here, we identify three r2r3 myb transcription factors regulating aliphatic glucosinolate biosynthesis in arabidopsis by combining several systems biology tools. | 2007 | 18094747 |
| tamsh7: a cereal mismatch repair gene that affects fertility in transgenic barley (hordeum vulgare l.). | chromosome pairing, recombination and dna repair are essential processes during meiosis in sexually reproducing organisms. investigating the bread wheat (triticum aestivum l.) ph2 (pairing homoeologous) locus has identified numerous candidate genes that may have a role in controlling such processes, including tamsh7, a plant specific member of the dna mismatch repair family. | 2007 | 18096080 |
| crystallization and preliminary x-ray studies of sdia from escherichia coli. | sdia enhances cell division by regulating the ftsqaz operon in escherichia coli as a transcription activator. in addition, sdia is suggested to play a role in detecting quorum signals that emanate from other species. it is therefore a homologue of luxr, a cognate quorum-sensing receptor that recognizes a quorum signal and activates the quorum responses. to elucidate the role of sdia and its functional and structural relationship to luxr, structural studies were performed on e. coli sdia. recombi ... | 2008 | 18097094 |