Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| identification of the syr-syp box in the promoter regions of genes dedicated to syringomycin and syringopeptin production by pseudomonas syringae pv. syringae b301d. | the phytotoxins syringopeptin and syringomycin are synthesized by nonribosomal peptide synthetases which are encoded by the syringomycin (syr) and syringopeptin (syp) genomic island of pseudomonas syringae pv. syringae. previous studies demonstrated that expression of the syr-syp genes was controlled by the sala-syrf regulatory pathway, which in turn was induced by plant signal molecules. in this study, the 132-kb syr-syp genomic island was found to be organized into five polycistronic operons a ... | 2006 | 16352832 |
| gene involved in transcriptional activation of the hrp regulatory gene hrpg in xanthomonas oryzae pv. oryzae. | a novel regulatory gene, trh, which is involved in hrp gene expression, is identified in the plant pathogen xanthomonas oryzae pv. oryzae. in the trh mutant, expression of hrpg, which is a key regulator for hrp gene expression, is reduced both under the in vitro hrp-inducing condition and in planta. | 2006 | 16707710 |
| altering glucosinolate profiles modulates disease resistance in plants. | plant diseases are major contributing factors for crop loss in agriculture. here, we show that arabidopsis plants with high levels of novel glucosinolates (gss) as a result of the introduction of single cyp79 genes exhibit altered disease resistance. arabidopsis expressing cyp79d2 from cassava accumulated aliphatic isopropyl and methylpropyl gs, and showed enhanced resistance against the bacterial soft-rot pathogen erwinia carotovora, whereas arabidopsis expressing the sorghum cyp79a1 or over-ex ... | 2006 | 16709192 |
| functional roles of the pepper pathogen-induced bzip transcription factor, cabzip1, in enhanced resistance to pathogen infection and environmental stresses. | transcription factors often belong to multigene families and their individual contribution in a particular regulatory network remains difficult to assess. we identify and functionally characterize the pepper bzip transcription factor cabzip1 gene isolated from pepper leaves infected with xanthomonas campestris pv. vesicatoria. transient expression analysis of the cabzip1-gfp fusion protein in arabidopsis protoplasts revealed that the cabzip1 protein is localized in the nucleus. the n-terminal re ... | 2006 | 16718483 |
| isolation of a novel abc-transporter gene from soybean induced by salicylic acid. | this paper reports on the identification and characterization of a new atp-binding cassette (abc) transporter which was identified as a salicylic acid-induced gene from soybean (glycine max cv. williams 82) in a subtractive suppression hybridization approach. a fragment of an abc-transporter gene was used to isolate a full-length cdna clone for this gene with a length of 4750 bp. the encoded protein has a length of 1447 amino acids and is composed of two similar repeat units typical of full-size ... | 2006 | 16720608 |
| fragments of atp synthase mediate plant perception of insect attack. | plants can perceive a wide range of biotic attackers and respond with targeted induced defenses. specificity in plant non-self-recognition occurs either directly by perception of pest-derived elicitors or indirectly through resistance protein recognition of host targets that are inappropriately proteolyzed. indirect plant perception can occur during interactions with pathogens, yet evidence for analogous events mediating the detection of insect herbivores remains elusive. here we report indirect ... | 2006 | 16720701 |
| [screening of mixed crop disease-resistant bacterial inoculants from n2-fixing and p-solubilzing bacterial isolates]. | in this paper, a total of 22 bacterial isolates capable of fixing nitrogen and/or solubilizing phosphorus were inoculated, and mixed incubated in 15 liquid media. the isolates were obtained from soil with selective media, and not purified. after grown for 48 hours, the mixed cultures were continuously inoculated to the same media, and then incubated under the same conditions. the procedures were repeated for 12 times, and 15 stable bacterial mixtures (sbm) were obtained. each sbm was purified, w ... | 2006 | 16724743 |
| improving the specificity of high-throughput ortholog prediction. | orthologs (genes that have diverged after a speciation event) tend to have similar function, and so their prediction has become an important component of comparative genomics and genome annotation. the gold standard phylogenetic analysis approach of comparing available organismal phylogeny to gene phylogeny is not easily automated for genome-wide analysis; therefore, ortholog prediction for large genome-scale datasets is typically performed using a reciprocal-best-blast-hits (rbh) approach. one ... | 2006 | 16729895 |
| de novo designed cyclic cationic peptides as inhibitors of plant pathogenic bacteria. | head-to-tail cyclic peptides of 4-10 residues consisting of alternating hydrophilic (lys) and hydrophobic (leu and phe) amino acids were synthesized and tested against the economically important plant pathogenic bacteria erwinia amylovora, xanthomonas vesicatoria and pseudomonas syringae. the antibacterial activity, evaluated as the minimal inhibitory concentration (mic), the cytotoxicity against human red blood cells and stability towards protease degradation were determined. the influence of c ... | 2006 | 16730857 |
| glycosylation of b-type flagellin of pseudomonas aeruginosa: structural and genetic basis. | the flagellin of pseudomonas aeruginosa can be classified into two major types-a-type or b-type-which can be distinguished on the basis of molecular weight and reactivity with type-specific antisera. flagellin from the a-type strain pak was shown to be glycosylated with a heterogeneous o-linked glycan attached to thr189 and ser260. here we show that b-type flagellin from strain pao1 is also posttranslationally modified with an excess mass of up to 700 da, which cannot be explained through phosph ... | 2006 | 16740946 |
| suicide vectors for antibiotic marker exchange and rapid generation of multiple knockout mutants by allelic exchange in gram-negative bacteria. | allelic exchange is frequently used in bacteria to generate knockout mutants in genes of interest, to carry out phenotypic analysis and learn about their function. frequently, understanding of gene function in complex processes such as pathogenesis requires the generation of multiple mutant strains. in pseudomonads and other non-enterobacteriaceae, this is a time-consuming and laborious process based on the use of suicide vectors and allelic exchange of the appropriate mutant version of each gen ... | 2006 | 16750581 |
| yersiniabactin production by pseudomonas syringae and escherichia coli, and description of a second yersiniabactin locus evolutionary group. | the siderophore and virulence factor yersiniabactin is produced by pseudomonas syringae. yersiniabactin was originally detected by high-pressure liquid chromatography (hplc); commonly used pcr tests proved ineffective. yersiniabactin production in p. syringae correlated with the possession of irp1 located in a predicted yersiniabactin locus. three similarly divergent yersiniabactin locus groups were determined: the yersinia pestis group, the p. syringae group, and the photorhabdus luminescens gr ... | 2006 | 16751485 |
| tomato qm-like protein protects saccharomyces cerevisiae cells against oxidative stress by regulating intracellular proline levels. | exogenous proline can protect cells of saccharomyces cerevisiae from oxidative stress. we altered intracellular proline levels by overexpressing the proline dehydrogenase gene (put1) of s. cerevisiae. put1p performs the first enzymatic step of proline degradation in s. cerevisiae. overexpression of put1p results in low proline levels and hypersensitivity to oxidants, such as hydrogen peroxide and paraquat. a put1-disrupted yeast mutant deficient in put1p activity has increased protection from ox ... | 2006 | 16751508 |
| subterfuge and manipulation: type iii effector proteins of phytopathogenic bacteria. | diverse gram-negative bacteria deliver effector proteins into the cells of their eukaryotic hosts using the type iii secretion system. collectively, these type iii effector proteins function to optimize the host cell environment for bacterial growth. type iii effector proteins are essential for the virulence of pseudomonas syringae, xanthomonas spp., ralstonia solanacearum and erwinia species. type iii secretion systems are also found in nonpathogenic pseudomonads and in species of symbiotic nit ... | 2006 | 16753033 |
| solution structure of arabidopsis thaliana protein at5g39720.1, a member of the aig2-like protein family. | the three-dimensional structure of arabidopsis thaliana protein at5g39720.1 was determined by nmr spectroscopy. it is the first representative structure of pfam family pf06094, which contains protein sequences similar to that of aig2, an a. thaliana protein of unknown function induced upon infection by the bacterial pathogen pseudomonas syringae. the at5g39720.1 structure consists of a five-stranded beta-barrel surrounded by two alpha-helices and a small beta-sheet. a long flexible alpha-helix p ... | 2006 | 16754964 |
| the bacterial twin-arginine translocation pathway. | the twin-arginine translocation (tat) pathway is responsible for the export of folded proteins across the cytoplasmic membrane of bacteria. substrates for the tat pathway include redox enzymes requiring cofactor insertion in the cytoplasm, multimeric proteins that have to assemble into a complex prior to export, certain membrane proteins, and proteins whose folding is incompatible with sec export. these proteins are involved in a diverse range of cellular activities including anaerobic metabolis ... | 2006 | 16756481 |
| iscr elements: novel gene-capturing systems of the 21st century? | "common regions" (crs), such as orf513, are being increasingly linked to mega-antibiotic-resistant regions. while their overall nucleotide sequences show little identity to other mobile elements, amino acid alignments indicate that they possess the key motifs of is91-like elements, which have been linked to the mobility ent plasmids in pathogenic escherichia coli. further inspection reveals that they possess an is91-like origin of replication and termination sites (teris), and therefore crs prob ... | 2006 | 16760305 |
| plant pathogen forensics: capabilities, needs, and recommendations. | a biological attack on u.s. crops, rangelands, or forests could reduce yield and quality, erode consumer confidence, affect economic health and the environment, and possibly impact human nutrition and international relations. preparedness for a crop bioterror event requires a strong national security plan that includes steps for microbial forensics and criminal attribution. however, u.s. crop producers, consultants, and agricultural scientists have traditionally focused primarily on strategies f ... | 2006 | 16760310 |
| improvement of cyclic decapeptides against plant pathogenic bacteria using a combinatorial chemistry approach. | cyclic decapeptides were developed based on the previously reported peptide c(lysleulysleulysphelysleulysgln). these compounds were active against the economically important plant pathogenic bacteria erwinia amylovora, pseudomonas syringae and xanthomonas vesicatoria. a library of 56 cyclic decapeptides was prepared and screened for antibacterial activity and eukaryotic cytotoxicity, and led to the identification of peptides with improved minimum inhibitory concentration (mic) against p. syringa ... | 2006 | 16762457 |
| cyp71b15 (pad3) catalyzes the final step in camalexin biosynthesis. | camalexin represents the main phytoalexin in arabidopsis (arabidopsis thaliana). the camalexin-deficient phytoalexin deficient 3 (pad3) mutant has been widely used to assess the biological role of camalexin, although the exact substrate of the cytochrome p450 enzyme 71b15 encoded by pad3 remained elusive. 2-(indol-3-yl)-4,5-dihydro-1,3-thiazole-4-carboxylic acid (dihydrocamalexic acid) was identified as likely intermediate in camalexin biosynthesis downstream of indole-3-acetaldoxime, as it accu ... | 2006 | 16766671 |
| biofilm formation and cellulose expression among diverse environmental pseudomonas isolates. | the ability to form biofilms is seen as an increasingly important colonization strategy among both pathogenic and environmental bacteria. a survey of 185 plant-associated, phytopathogenic, soil and river pseudomonas isolates resulted in 76% producing biofilms at the air-liquid (a-l) interface after selection in static microcosms. considerable variation in biofilm phenotype was observed, including waxy aggregations, viscous and floccular masses, and physically cohesive biofilms with continuously ... | 2006 | 17014498 |
| the three-dimensional structure of the flagellar rotor from a clockwise-locked mutant of salmonella enterica serovar typhimurium. | three-dimensional reconstructions from electron cryomicrographs of the rotor of the flagellar motor reveal that the symmetry of individual m rings varies from 24-fold to 26-fold while that of the c rings, containing the two motor/switch proteins flim and flin, varies from 32-fold to 36-fold, with no apparent correlation between the symmetries of the two rings. results from other studies provided evidence that, in addition to the transmembrane protein flif, at least some part of the third motor/s ... | 2006 | 17015643 |
| survival and growth in the presence of elevated copper: transcriptional profiling of copper-stressed pseudomonas aeruginosa. | transcriptional profiles of pseudomonas aeruginosa exposed to two separate copper stress conditions were determined. actively growing bacteria subjected to a pulse of elevated copper for a short period of time was defined as a "copper-shocked" culture. conversely, copper-adapted populations were defined as cells actively growing in the presence of elevated copper. expression of 405 genes changed in the copper-shocked culture, compared to 331 genes for the copper-adapted cultures. not surprisingl ... | 2006 | 17015663 |
| the genome sequence of mannheimia haemolytica a1: insights into virulence, natural competence, and pasteurellaceae phylogeny. | the draft genome sequence of mannheimia haemolytica a1, the causative agent of bovine respiratory disease complex (brdc), is presented. strain atcc baa-410, isolated from the lung of a calf with brdc, was the dna source. the annotated genome includes 2,839 coding sequences, 1,966 of which were assigned a function and 436 of which are unique to m. haemolytica. through genome annotation many features of interest were identified, including bacteriophages and genes related to virulence, natural comp ... | 2006 | 17015664 |
| the aaur-aaus two-component system regulates uptake and metabolism of acidic amino acids in pseudomonas putida. | pseudomonas putida kt2440 metabolizes a wide range of carbon and nitrogen sources, including many amino acids. in this study, a sigma54-dependent two-component system that controls the uptake and metabolism of acidic amino acids was identified. the system (designated aau, for acidic amino acid utilization) involves a sensor histidine kinase, aaus, encoded by pp1067, and a response regulator, aaur, encoded by pp1066. aaur and aaus deletion mutants were unable to efficiently utilize aspartate (asp ... | 2006 | 17021207 |
| occurrence of sep insecticidal toxin complex genes in serratia spp. and yersinia frederiksenii. | some strains of serratia entomophila and s. proteamaculans cause amber disease of the grass grub costelytra zealandica (coleoptera: scarabaeidae). three genes required for virulence, sepabc, are located on a large plasmid, padap. sequence analysis suggests that the sepabc gene cluster may be part of a horizontally mobile region. this study presents evidence for the putative mobility of the sep genes of padap. southern blot analysis showed that orthologues of the sep genes reside on plasmids with ... | 2006 | 17021209 |
| yeast increases resistance in arabidopsis against pseudomonas syringae and botrytis cinerea by salicylic acid-dependent as well as -independent mechanisms. | cell-wall and glucopeptide components of yeast have been reported to exhibit elicitor activity. the mode of action of defense activation by yeast is not known so far. in this study, we used the model plant arabidopsis to investigate the activation of defense responses by yeast, the effect on resistance against different pathogens, and the mode of action. treatment of arabidopsis plants with an autoclaved yeast suspension induced the expression of systemic acquired resistance-related genes and ac ... | 2006 | 17022178 |
| the pti1-like kinase zmpti1a from maize (zea mays l.) co-localizes with callose at the plasma membrane of pollen and facilitates a competitive advantage to the male gametophyte. | the tomato kinase pto confers resistance to bacterial speck disease caused by pseudomonas syringae pv. tomato in a gene for gene manner. upon recognition of specific avirulence factors the pto kinase activates multiple signal transduction pathways culminating in induction of pathogen defense. the soluble cytoplasmic serine/threonine kinase pti1 is one target of pto phosphorylation and is involved in the hypersensitive response (hr) reaction. however, a clear role of pti1 in plant pathogen resist ... | 2006 | 17022830 |
| modifications to the arabidopsis defense proteome occur prior to significant transcriptional change in response to inoculation with pseudomonas syringae. | alterations in the proteome of arabidopsis (arabidopsis thaliana) leaves during responses to challenge by pseudomonas syringae pv tomato dc3000 were analyzed using two-dimensional gel electrophoresis. protein changes characteristic of the establishment of disease, basal resistance, and resistance-gene-mediated resistance were examined by comparing responses to dc3000, a hrp mutant, and dc3000 expressing avrrpm1, respectively. the abundance of each protein identified was compared with that of sel ... | 2006 | 17028151 |
| the tomato nbarc-lrr protein prf interacts with pto kinase in vivo to regulate specific plant immunity. | immunity in tomato (solanum lycopersicum) to pseudomonas syringae bacteria expressing the effector proteins avrpto and avrptob requires both pto kinase and the nbarc-lrr (for nucleotide binding domain shared by apaf-1, certain r gene products, and ced-4 fused to c-terminal leucine-rich repeats) protein prf. pto plays a direct role in effector recognition within the host cytoplasm, but the role of prf is unknown. we show that pto and prf are coincident in the signal transduction pathway that cont ... | 2006 | 17028203 |
| a homologue of the 3-oxoacyl-(acyl carrier protein) synthase iii gene located in the glycosylation island of pseudomonas syringae pv. tabaci regulates virulence factors via n-acyl homoserine lactone and fatty acid synthesis. | pseudomonas syringae pv. tabaci 6605 possesses a genetic region involved in flagellin glycosylation. this region is composed of three open reading frames: orf1, orf2, and orf3. our previous study revealed that orf1 and orf2 encode glycosyltransferases; on the other hand, orf3 has no role in posttranslational modification of flagellin. although the function of orf3 remained unclear, an orf3 deletion mutant (deltaorf3 mutant) had reduced virulence on tobacco plants. orf3 shows significant homology ... | 2006 | 17028280 |
| pr genes of apple: identification and expression in response to elicitors and inoculation with erwinia amylovora. | in the past decade, much work has been done to dissect the molecular basis of the defence signalling pathway in plants known as systemic acquired resistance (sar). most of the work has been carried out in model species such as arabidopsis, with little attention paid to woody plants. however within the range of species examined, components of the pathway seem to be highly conserved. in this study, we attempted to identify downstream components of the sar pathway in apple to serve as markers for i ... | 2006 | 17029637 |
| early responsive to dehydration 15, a negative regulator of abscisic acid responses in arabidopsis. | early responsive to dehydration 15 (erd15) is rapidly induced in response to various abiotic and biotic stress stimuli in arabidopsis (arabidopsis thaliana). modulation of erd15 levels by overexpression or rnai silencing altered the responsiveness of the transgenic plants to the phytohormone abscisic acid (aba). overexpression of erd15 reduced the aba sensitivity of arabidopsis manifested in decreased drought tolerance and in impaired ability of the plants to increase their freezing tolerance in ... | 2006 | 17056758 |
| arabidopsis wrky33 transcription factor is required for resistance to necrotrophic fungal pathogens. | plant wrky transcription factors are key regulatory components of plant responses to microbial infection. in addition to regulating the expression of defense-related genes, wrky transcription factors have also been shown to regulate cross-talk between jasmonate- and salicylate-regulated disease response pathways. the two pathways mediate resistance against different types of microbial pathogens, and there are numerous reports of antagonistic interactions between them. here we show that mutations ... | 2006 | 17059405 |
| the arabidopsis map kinase kinase mkk1 participates in defence responses to the bacterial elicitor flagellin. | plants sense pathogens through both pathogen-associated molecular patterns and recognition of race-specific virulence factors, which induce basal defence or an accelerated defence (often manifest in the form of local cell death), respectively. a mitogen-activated protein kinase (mapk) module in arabidopsis was previously proposed to signal from perception of the bacterial elicitor flagellin to the activation of basal defence-related genes. here, we present evidence for a parallel mapk-signalling ... | 2006 | 17059410 |
| evolution of the yellow/major royal jelly protein family and the emergence of social behavior in honey bees. | the genomic architecture underlying the evolution of insect social behavior is largely a mystery. eusociality, defined by overlapping generations, parental brood care, and reproductive division of labor, has most commonly evolved in the hymenopteran insects, including the honey bee apis mellifera. in this species, the major royal jelly protein (mrjp) family is required for all major aspects of eusocial behavior. here, using data obtained from the a. mellifera genome sequencing project, we demons ... | 2006 | 17065613 |
| using the nucleotide substitution rate matrix to detect horizontal gene transfer. | horizontal gene transfer (hgt) has allowed bacteria to evolve many new capabilities. because transferred genes perform many medically important functions, such as conferring antibiotic resistance, improved detection of horizontally transferred genes from sequence data would be an important advance. existing sequence-based methods for detecting hgt focus on changes in nucleotide composition or on differences between gene and genome phylogenies; these methods have high error rates. | 2006 | 17067382 |
| flagellin suppresses epithelial apoptosis and limits disease during enteric infection. | flagellin, the primary component of bacterial flagella, is a potent activator of toll-like receptor 5 (tlr5) signaling and is a major proinflammatory determinant of enteropathogenic salmonella. in accordance with this, we report here that aflagellate salmonella mutants are impaired in their ability to up-regulate proinflammatory and anti-apoptotic effector molecules in murine models of salmonellosis and that these mutants elicit markedly reduced early mucosal inflammation relative to their isoge ... | 2006 | 17071592 |
| a pathogen-inducible endogenous sirna in plant immunity. | rna interference, mediated by small interfering rnas (sirnas), is a conserved regulatory process that has evolved as an antiviral defense mechanism in plants and animals. it is not known whether host cells also use sirnas as an antibacterial defense mechanism in eukaryotes. here, we report the discovery of an endogenous sirna, nat-sirnaatgb2, that is specifically induced by the bacterial pathogen pseudomonas syringae carrying effector avrrpt2. we demonstrate that the biogenesis of this sirna req ... | 2006 | 17071740 |
| arabidopsis displays centromeric dna hypomethylation and cytological alterations of heterochromatin upon attack by pseudomonas syringae. | plant tissues display major alterations upon the perception of microbial pathogens. changes of cytoplasmic and apoplastic components that sense and transduce plant defenses have been extensively characterized. in contrast, less information is available about modifications affecting the plant nuclear genome under these circumstances. here, we investigated whether the arabidopsis thaliana dna methylation status is altered in tissues responding to the attack of pseudomonas syringae pv. tomato dc300 ... | 2006 | 16776291 |
| the erwinia amylovora avrrpt2ea gene contributes to virulence on pear and avrrpt2ea is recognized by arabidopsis rps2 when expressed in pseudomonas syringae. | the enterobacterium erwinia amylovora is a devastating plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. in an attempt to identify genes induced during infection of host plants, we identified and cloned a putative effector gene, avrrpt2ea. the deduced amino-acid sequence of the translated avrrpt2ea protein is homologous to the effector protein avrrpt2 previously reported in pseudomonas syringae pv. tomato. these two proteins share 58% identity (7 ... | 2006 | 16776298 |
| the arabidopsis flavin-dependent monooxygenase fmo1 is an essential component of biologically induced systemic acquired resistance. | upon localized attack by necrotizing pathogens, plants gradually develop increased resistance against subsequent infections at the whole-plant level, a phenomenon known as systemic acquired resistance (sar). to identify genes involved in the establishment of sar, we pursued a strategy that combined gene expression information from microarray data with pathological characterization of selected arabidopsis (arabidopsis thaliana) t-dna insertion lines. a gene that is up-regulated in arabidopsis lea ... | 2006 | 16778014 |
| the pto kinase of tomato, which regulates plant immunity, is repressed by its myristoylated n terminus. | specific recognition of the pseudomonas syringae effector proteins avrpto and avrptob in tomato is mediated by pto kinase resulting in induction of defense responses, including hypersensitive cell death via a signaling pathway requiring the nucleotide-binding leucine-rich repeats protein prf. pto is a myristoylated protein, and n-myristoylation is required for signaling. here we demonstrated a role for n-myristoylation in controlling pto kinase activity. a myristoylated peptide corresponding to ... | 2006 | 16785235 |
| casar82a, a pathogen-induced pepper sar8.2, exhibits an antifungal activity and its overexpression enhances disease resistance and stress tolerance. | pepper sar8.2 gene (casar82a) was previously reported to be locally or systemically induced in pepper plants by biotic and abiotic stresses. in this study, the physiological and molecular functions of the pepper sar8.2 protein in the plant defense responses were investigated by generating arabidopsis transgenic lines overexpressing the casar82a gene. the transgenic arabidopsis plants grew faster than the wild-type plants, indicating that the casar82a gene was involved in plant development. the e ... | 2006 | 16786294 |
| auxin flow in anther filaments is critical for pollen grain development through regulating pollen mitosis. | it was well known that auxin is critical for anther/pollen grain development, however, the clear distribution and detailed effects of auxin during floral development are still unclear. we have shown here that, through analyzing gus activities of arabidopsis lines harboring auxin response elements dr5-gus, auxin was mainly accumulated in the anther during flower stages 10-12. further studies employing the indoleacetic acid-lysine synthetase (iaal) coding gene from pseudomonas syringae subsp. sava ... | 2006 | 16786302 |
| genomic analysis of carbon source metabolism of shewanella oneidensis mr-1: predictions versus experiments. | genomic sequences have been used to find the genetic foundation for carbon source metabolism in shewanella oneidensis mr-1. annotated s. oneidensis mr-1 gene products were examined for their sequence similarity to enzymes participating in pathways for utilization of carbon and energy as described in the biocyc database (http://www.biocyc.org/) or in the primary literature. a picture emerges that relegates five- and six-carbon sugars to minor roles as carbon sources, whereas multiple pathways for ... | 2006 | 16788168 |
| erwinia carotovora subspecies produce duplicate variants of expr, luxr homologs that activate rsma transcription but differ in their interactions with n-acylhomoserine lactone signals. | the n-acylhomoserine lactone (ahl) signaling system comprises a producing system that includes acylhomoserine synthase (ahli, a luxi homolog) and a receptor, generally a luxr homolog. ahl controls exoprotein production in erwinia carotovora and consequently the virulence for plants. in previous studies we showed that expr, a luxr homolog, is an ahl receptor and that it activates transcription of rsma, the gene encoding an rna binding protein which is a global negative regulator of exoproteins an ... | 2006 | 16788181 |
| popf1 and popf2, two proteins secreted by the type iii protein secretion system of ralstonia solanacearum, are translocators belonging to the hrpf/nopx family. | ralstonia solanacearum gmi1000 is a gram-negative plant pathogen which contains an hrp gene cluster which codes for a type iii protein secretion system (ttss). we identified two novel hrp-secreted proteins, called popf1 and popf2, which display similarity to one another and to putative ttss translocators, hrpf and nopx, from xanthomonas spp. and rhizobia, respectively. they also show similarities with ttss translocators of the yopb family from animal-pathogenic bacteria. both popf1 and popf2 bel ... | 2006 | 16788199 |
| type iii secretion-dependent modulation of innate immunity as one of multiple factors regulated by pseudomonas aeruginosa rets. | mutation of rets (rtsm) of pseudomonas aeruginosa strain pa103 reduces its virulence in both ocular and respiratory murine models of infection. in vitro, rets mutants exhibit loss of the exsa-regulated type iii secretion system (ttss), reduced twitching motility, and a decrease in association with, invasion of, and survival within corneal epithelial cells. in addition, transcription of multiple other virulence genes is positively and negatively affected by rets mutation. since our published data ... | 2006 | 16790760 |
| pseudomonas syringae effector avrptob suppresses basal defence in arabidopsis. | the virulence and avirulence activities of members of the pseudomonas syringae hopab family of effectors and avrpto were examined in bean, tomato and arabidopsis. proteins were delivered by the rw60 strain of p. syringae pv. phaseolicola. rw60 causes a hypersensitive reaction (hr) in bean and tomato but is restricted without the hr in arabidopsis. dual avirulence and virulence functions in tomato and bean, respectively, were identified in virppha homologues but only avrptob strongly enhanced vir ... | 2006 | 16792692 |
| construction of a bacterial artificial chromosome library and characterization of hrp/hrc gene cluster of pseudomonas syringae pathovar tagetis lmg5090. | pseudomonas syringae pv. tagetis causes apical chlorosis of several plant species in the asteraceae, including marigold. as a means to facilitate the isolation of pathogenicity genes and to characterize the genome of this bacterium, we have constructed a bacterial artificial chromosome library of p. syringae pv. tagetis strain lmg5090. the library consists of 1,536 clones with insert size ranging from 30 to 160 kb and an average size of 86 kb. based upon colony hybridization, the bac clone 420e2 ... | 2006 | 16799767 |
| quantitative in situ assay of salicylic acid in tobacco leaves using a genetically modified biosensor strain of acinetobacter sp. adp1. | salicylic acid (sa) plays important roles in plants, most notably in the induction of systemic acquired resistance (sar) against pathogens. a non-destructive in situ assay for sa would provide new insights into the functions of sa in sar and other sa-regulated phenomena. we assessed a genetically engineered strain of acinetobacter sp. adp1, which proportionally produces bioluminescence in response to salicylates including sa and methylsalicylate, as a reporter for salicylate accumulation in the ... | 2006 | 16805738 |
| closing the circle on the discovery of genes encoding hrp regulon members and type iii secretion system effectors in the genomes of three model pseudomonas syringae strains. | pseudomonas syringae strains translocate large and distinct collections of effector proteins into plant cells via the type iii secretion system (t3ss). mutations in t3ss-encoding hrp genes are unable to elicit the hypersensitive response or pathogenesis in nonhost and host plants, respectively. mutations in individual effectors lack strong phenotypes, which has impeded their discovery. p. syringae effectors are designated hop (hrp outer protein) or avr (avirulence) proteins. some hop proteins ar ... | 2006 | 17073298 |
| regulation of the type iii secretion system in phytopathogenic bacteria. | the type iii secretion system (ttss) is a specialized protein secretion machinery used by numerous gram-negative bacterial pathogens of animals and plants to deliver effector proteins directly into the host cells. in plant-pathogenic bacteria, genes encoding the ttss were discovered as hypersensitive response and pathogenicity (hrp) genes, because mutation of these genes typically disrupts the bacterial ability to cause diseases on host plants and to elicit hypersensitive response on nonhost pla ... | 2006 | 17073299 |
| whole-genome expression profiling defines the hrpl regulon of pseudomonas syringae pv. tomato dc3000, allows de novo reconstruction of the hrp cis clement, and identifies novel coregulated genes. | pseudomonas syringae pv. tomato dc3000 is a model pathogen of tomato and arabidopsis that uses a hypersensitive response and pathogenicity (hrp) type iii secretion system (t3ss) to deliver virulence effector proteins into host cells. expression of the hrp system and many effector genes is activated by the hrpl alternative sigma factor. here, an open reading frame-specific whole-genome microarray was constructed for dc3000 and used to comprehensively identify genes that are differentially express ... | 2006 | 17073300 |
| multiple approaches to a complete inventory of pseudomonas syringae pv. tomato dc3000 type iii secretion system effector proteins. | pseudomonas syringae pv. tomato dc3000 is a pathogen of tomato and arabidopsis that translocates virulence effector proteins into host cells via a type iii secretion system (t3ss). many effector-encoding hypersensitive response and pathogenicity (hrp) outer protein (hop) genes have been identified previously in dc3000 using bioinformatic methods based on hrp promoter sequences and characteristic n-terminal amino acid patterns that are associated with t3ss substrates. to approach completion of th ... | 2006 | 17073301 |
| bioinformatics-enabled identification of the hrpl regulon and type iii secretion system effector proteins of pseudomonas syringae pv. phaseolicola 1448a. | the ability of pseudomonas syringae pv. phaseolicola to cause halo blight of bean is dependent on its ability to translocate effector proteins into host cells via the hypersensitive response and pathogenicity (hrp) type iii secretion system (t3ss). to identify genes encoding type iii effectors and other potential virulence factors that are regulated by the hrpl alternative sigma factor, we used a hidden markov model, weight matrix model, and type iii targeting-associated patterns to search the g ... | 2006 | 17073302 |
| salmonella produces an o-antigen capsule regulated by agfd and important for environmental persistence. | in this study, we show that salmonella produces an o-antigen capsule coregulated with the fimbria- and cellulose-associated extracellular matrix. structural analysis of purified salmonella extracellular polysaccharides yielded predominantly a repeating oligosaccharide unit similar to that of salmonella enterica serovar enteritidis lipopolysaccharide o antigen with some modifications. putative carbohydrate transport and regulatory operons important for capsule assembly and translocation, designat ... | 2006 | 17079680 |
| from the academy: colloquium review. unique characteristics of xanthomonas oryzae pv. oryzae avrxa21 and implications for plant innate immunity. | this article provides a brief overview of some of the major concepts and molecular features of plant and animal innate immune systems. the rice pathogen recognition receptor, xa21, confers resistance to xanthomonas oryzae pv. oryzae strains producing the avrxa21 elicitor. xa21 codes for a receptor-like kinase consisting of an extracellular leucine-rich repeat domain, a transmembrane domain, and a cytoplasmic kinase domain. we show that avrxa21 activity requires the presence of rax (required for ... | 2006 | 17082309 |
| transcriptome changes in the phenylpropanoid pathway of glycine max in response to pseudomonas syringae infection. | reports of plant molecular responses to pathogenic infections have pinpointed increases in activity of several genes of the phenylpropanoid pathway leading to the synthesis of lignin and flavonoids. the majority of those findings were derived from single gene studies and more recently from several global gene expression analyses. we undertook a global transcriptional analysis focused on the response of genes of the multiple branches of the phenylpropanoid pathway to infection by the pseudomonas ... | 2006 | 17083738 |
| substrate recognition, protein dynamics, and iron-sulfur cluster in pseudomonas aeruginosa adenosine 5'-phosphosulfate reductase. | aps reductase catalyzes the first committed step of reductive sulfate assimilation in pathogenic bacteria, including mycobacterium tuberculosis, and is a promising target for drug development. we report the 2.7 a resolution crystal structure of pseudomonas aeruginosa aps reductase in the thiosulfonate intermediate form of the catalytic cycle and with substrate bound. the structure, high-resolution fourier transform ion cyclotron resonance (ft-icr) mass spectrometry, and quantitative kinetic anal ... | 2006 | 17010373 |
| the algt gene of pseudomonas syringae pv. glycinea and new insights into the transcriptional organization of the algt-muc gene cluster. | the phytopathogenic bacterium pseudomonas syringae pv. glycinea infects soybean plants and causes bacterial blight. in addition to p. syringae, the human pathogen pseudomonas aeruginosa and the soil bacterium azotobacter vinelandii produce the exopolysaccharide alginate, a copolymer of d-mannuronic and l-guluronic acids. alginate production in p. syringae has been associated with increased fitness and virulence in planta. alginate biosynthesis is tightly controlled by proteins encoded by the alg ... | 2006 | 17012388 |
| contribution of ethylene biosynthesis for resistance to blast fungus infection in young rice plants. | the role of ethylene (et) in resistance to infection with blast fungus (magnaporthe grisea) in rice (oryza sativa) is poorly understood. to study it, we quantified et levels after inoculation, using young rice plants at the four-leaf stage of rice cv nipponbare (wild type) and its isogenic plant (il7), which contains the pi-i resistance gene to blast fungus race 003. small necrotic lesions by hypersensitive reaction (hr) were formed at 42 to 72 h postinoculation (hpi) in resistant il7 leaves, an ... | 2006 | 17012402 |
| ndr1 interaction with rin4 mediates the differential activation of multiple disease resistance pathways in arabidopsis. | recognition of pathogens by plants involves the coordinated efforts of molecular chaperones, disease resistance (r) proteins, and components of disease resistance signaling pathways. characterization of events associated with pathogen perception in arabidopsis thaliana has advanced understanding of molecular genetic mechanisms associated with disease resistance and protein interactions critical for the activation of resistance signaling. regulation of r protein-mediated signaling in response to ... | 2006 | 17012600 |
| induction of a salicylic acid glucosyltransferase, atsgt1, is an early disease response in arabidopsis thaliana. | endogenous salicylic acid (sa) and its predominant conjugates, sa 2-o-beta-d-glucoside (sag) and the glucose ester of sa (sge), increase dramatically during plant defense responses. here i report the isolation and characterization of an arabidopsis thaliana udp-glucose:sa glucosyltransferase1 (atsgt1) gene using a tobacco sgt gene previously reported, whose product catalyzes the formation of both sag and sge. the recombinant atsgt1 protein had significant activities with sa and benzoic acid, and ... | 2006 | 17085977 |
| [molecular cloning and characterization of a novel wrky gene from brassica chinensis]. | a new wrky gene was cloned from brassica chinensis by rapid amplification of cdna ends (race). the full-length cdna of bcwrky was 1175 bp long and contained a 924 bp open reading frame (orf) encoding a putative w-box-binding protein of 308 amino acids. the predicted bcwrky protein was found to have a potential bipartite nuclear localization sequence (nls-bp) in its n-terminal region followed by a wrky dna-binding domain. bioinformatic analysis revealed that bcwrky resembled other wrky domain-con ... | 2006 | 17086982 |
| syringolin a, a new plant elicitor from the phytopathogenic bacterium pseudomonas syringae pv. syringae, inhibits the proliferation of neuroblastoma and ovarian cancer cells and induces apoptosis. | syringolin a is a new plant elicitor produced by the plant pathogen pseudomonas syringae pv. syringae. the goal of this study was to investigate whether syringolin a exhibits anti-proliferative properties in cancer cells. the treatment of human neuroblastoma (nb) cells (sk-n-sh and lan-1) and human ovarian cancer cells (skov3) with syringolin a (0-100 microm) inhibited cell proliferation in a dose-dependent manner. the ic(50) (50% inhibition) for each cell line ranged between 20 microm and 25 mi ... | 2006 | 17109642 |
| protein polyubiquitination plays a role in basal host resistance of barley. | to study protein ubiquitination pathways in the interaction of barley (hordeum vulgare) with the powdery mildew fungus (blumeria graminis), we measured protein turnover and performed transient-induced gene silencing (tigs) of ubiquitin and 26s proteasome subunit encoding genes in epidermal cells. attack by b. graminis hyperdestabilized a novel unstable green fluorescent protein fusion that contains a destabilization domain of a putative barley 1-aminocyclopropane-1-carboxylate synthase, suggesti ... | 2006 | 17114351 |
| the transcription factors wrky11 and wrky17 act as negative regulators of basal resistance in arabidopsis thaliana. | transcription factors are believed to play a pivotal role in the activation and fine-tuning of plant defense responses, but little is known about the exact function of individual transcription factors in this process. we analyzed the role of the iid subfamily of wrky transcription factors in the regulation of basal resistance to pseudomonas syringae pv tomato (pst). the expression of four members of the subfamily was induced upon challenge with virulent and avirulent strains of pst. mutant analy ... | 2006 | 17114354 |
| a constitutive shade-avoidance mutant implicates tir-nbs-lrr proteins in arabidopsis photomorphogenic development. | in plants, light signals caused by the presence of neighbors accelerate stem growth and flowering and induce a more erect position of the leaves, a developmental strategy known as shade-avoidance syndrome. in addition, mutations in the photoreceptors that mediate shade-avoidance responses enhance disease susceptibility in arabidopsis thaliana. here, we describe the arabidopsis constitutive shade-avoidance1 (csa1) mutant, which shows a shade-avoidance phenotype in the absence of shade and enhance ... | 2006 | 17114357 |
| overexpression of gberf confers alteration of ethylene-responsive gene expression and enhanced resistance to pseudomonas syringae in transgenic tobacco. | gberf belongs to the erf (ethylene responsive factor) family of transcription factors and regulates the gcc-box containing pathogen-related (pr) genes in the ethylene signal transduction pathway. to study the function of gberf in the process of biotic stress, transgenic tobacco plants expressing gberf were generated. overexpression of gberf did not change transgenic plant's phenotype and endogenous ethylene level. however, the expression profile of some ethylene-inducible gcc-box and non-gcc-box ... | 2006 | 16809858 |
| efficient virus-induced gene silencing in arabidopsis. | virus-induced gene silencing (vigs) is a plant rna-silencing technique that uses viral vectors carrying a fragment of a gene of interest to generate double-stranded rna, which initiates the silencing of the target gene. several viral vectors have been developed for vigs and they have been successfully used in reverse genetics studies of a variety of processes occurring in plants. this approach has not been widely adopted for the model dicotyledonous species arabidopsis (arabidopsis thaliana), po ... | 2006 | 16815951 |
| the brucella abortus cyclic beta-1,2-glucan virulence factor is substituted with o-ester-linked succinyl residues. | brucella periplasmic cyclic beta-1,2-glucan plays an important role during bacterium-host interaction. nuclear magnetic resonance spectrometry analysis, thin-layer chromatography, and deae-sephadex chromatography were used to characterize brucella abortus cyclic glucan. in the present study, we report that a fraction of b. abortus cyclic beta-1,2-glucan is substituted with succinyl residues, which confer anionic character on the cyclic beta-1,2-glucan. the oligosaccharide backbone is substituted ... | 2006 | 16816173 |
| an arabidopsis homologue of human seven-in-absentia-interacting protein is involved in pathogen resistance. | human seven-in-absentia (siah)-interacting protein (sip) is a component of the e3 ligase complex targeting beta-catenin for destruction. arabidopsis has one sip protein (atsip) with 32% amino acid sequence identity to sip. to investigate the functions of atsip, we isolated an atsip knockout mutant, and generated transgenic plants overexpressing atsip. the growth rates and morphologies of the atsip and transgenic plants were indistinguishable from those of wild type. however, atsip plants were mo ... | 2006 | 16819302 |
| prediction of csra-regulating small rnas in bacteria and their experimental verification in vibrio fischeri. | the role of small rnas as critical components of global regulatory networks has been highlighted by several recent studies. an important class of such small rnas is represented by csrb and csrc of escherichia coli, which control the activity of the global regulator csra. given the critical role played by csra in several bacterial species, an important problem is the identification of csra-regulating small rnas. in this paper, we develop a computer program (csrna_find) designed to locate potentia ... | 2006 | 16822857 |
| double hexameric ring assembly of the type iii protein translocase atpase hrcn. | the specialized type iii secretion (t3s) apparatus of pathogenic and symbiotic gram-negative bacteria comprises a complex transmembrane organelle and an atpase homologous to the f1-atpase beta subunit. the t3s atpase hrcn of pseudomonas syringae associates with the inner membrane, and its atp hydrolytic activity is stimulated by dodecamerization. the structure of dodecameric hrcn (hrcn12) determined to 1.6 nm by cryo-electron microscopy is presented. hrcn12 comprises two hexameric rings that are ... | 2006 | 16824099 |
| a mutation in the gtp hydrolysis site of arabidopsis dynamin-related protein 1e confers enhanced cell death in response to powdery mildew infection. | we screened for mutants of arabidopsis thaliana that displayed enhanced disease resistance to the powdery mildew pathogen erysiphe cichoracearum and identified the edr3 mutant, which formed large gray lesions upon infection with e. cichoracearum and supported very little sporulation. the edr3-mediated disease resistance and cell death phenotypes were dependent on salicylic acid signaling, but independent of ethylene and jasmonic acid signaling. in addition, edr3 plants displayed enhanced suscept ... | 2006 | 16824181 |
| functional expression of mammalian nadph-cytochrome p450 oxidoreductase on the cell surface of escherichia coli. | to develop a whole-cell oxidoreductase system without the practical limitation of substrate/product transport, easy preparation, stability of enzymes, and low expression levels, we here report the development of a whole cell biocatalyst displaying rat nadph-cytochrome p450 oxidoreductase (cpr, 77-kda) on the surface of escherichia coli by using ice-nucleation protein from pseudomonas syringae. surface localization and functionality of the cpr were verified by flow cytometry, electron microscopy, ... | 2006 | 16829136 |
| herbivore-induced resistance against microbial pathogens in arabidopsis. | caterpillars of the herbivore pieris rapae stimulate the production of jasmonic acid (ja) and ethylene (et) in arabidopsis (arabidopsis thaliana) and trigger a defense response that affects insect performance on systemic tissues. to investigate the spectrum of effectiveness of p. rapae-induced resistance, we examined the level of resistance against different pathogens. although the necrotrophic fungus alternaria brassicicola is sensitive to ja-dependent defenses, herbivore-induced resistance was ... | 2006 | 16829584 |
| corr regulates multiple components of virulence in pseudomonas syringae pv. tomato dc3000. | the phytotoxin coronatine (cor) is produced by various pathovars of pseudomonas syringae, including p. syringae pv. tomato dc3000, which is pathogenic on crucifers and tomato, and p. syringae pv. glycinea pg4180, a soybean pathogen. the cor molecule contains two distinct components, coronafacic acid (cfa) and coronamic acid (cma), which are intermediates in the cor biosynthetic pathway. in p. syringae pv. tomato dc3000, it is not clear whether corr, which encodes a response regulator, positively ... | 2006 | 16838789 |
| the arabidopsis thaliana jasmonate insensitive 1 gene is required for suppression of salicylic acid-dependent defenses during infection by pseudomonas syringae. | many plant pathogens suppress antimicrobial defenses using virulence factors that modulate endogenous host defenses. the pseudomonas syringae phytotoxin coronatine (cor) is believed to promote virulence by acting as a jasmonate analog, because cor-insensitive 1 (coil) arabidopsis thaliana and tomato mutants are impaired in jasmonate signaling and exhibit reduced susceptibility to p. syringae. to further investigate the role of jasmonate signaling in disease development, we analyzed several jasmo ... | 2006 | 16838791 |
| a bacterial virulence protein suppresses host innate immunity to cause plant disease. | plants have evolved a powerful immune system to defend against infection by most microbial organisms. however, successful pathogens, such as pseudomonas syringae, have developed countermeasures and inject virulence proteins into the host plant cell to suppress immunity and cause devastating diseases. despite intensive research efforts, the molecular targets of bacterial virulence proteins that are important for plant disease development have remained obscure. here, we show that a conserved p. sy ... | 2006 | 16840699 |
| polyamine oxidase is one of the key elements for oxidative burst to induce programmed cell death in tobacco cultured cells. | programmed cell death plays a critical role during the hypersensitive response in the plant defense system. one of components that triggers it is hydrogen peroxide, which is generated through multiple pathways. one example is proposed to be polyamine oxidation, but direct evidence for this has been limited. in this article, we investigated relationships among polyamine oxidase, hydrogen peroxide, and programmed cell death using a model system constituted of tobacco (nicotiana tabacum) cultured c ... | 2006 | 16844838 |
| tobacco tsip1, a dnaj-type zn finger protein, is recruited to and potentiates tsi1-mediated transcriptional activation. | tobacco stress-induced1 (tsi1) is an ethylene-responsive-element binding protein/apetala2-type transcription factor that plays an important role in both biotic and abiotic stress signaling pathways. we show that tsi1-interacting protein1 (tsip1), a dnaj-type zn finger protein, interacts with tsi1 in vitro and in yeast (saccharomyces cerevisiae). the transcript level of tsip1 in tobacco (nicotiana tabacum) increased upon treatment with salicylic acid (sa), ethylene, gibberellic acid, nacl, and vi ... | 2006 | 16844903 |
| development of a virus-induced gene-silencing system for functional analysis of the rps2-dependent resistance signalling pathways in arabidopsis. | virus-induced gene silencing (vigs) offers a rapid and high throughput technique platform for the analysis of gene function in plants. although routinely used in some solanaceous species, vigs system has not been well established in arabidopsis thaliana (l.) heynh. we have recently reported some factors that potentially influence tobacco rattle virus (trv)-mediated vigs of phytoene desaturase (pds) and actin gene expression in arabidopsis. in this study, we have further established that the agro ... | 2006 | 16845481 |
| the defh9-iaam-containing construct efficiently induces parthenocarpy in cucumber. | parthenocarpy (seedless fruits) is a desirable trait that has been achieved in many plant cultivars. we generated parthenocarpic cucumber fruits by introducing the chimeric defh9-iaam construct into the cucumber genome using an agrobacterium tumefaciens-mediated protocol. the construct consists of the defh9 promoter from antirrhinum majus and the iaam coding sequence from pseudomonas syringae. transgenic plants were obtained from nine independent transformation events: half of these were tetrapl ... | 2006 | 16847572 |
| analysis of the defence phosphoproteome of arabidopsis thaliana using differential mass tagging. | despite recent advances in proteomic technologies, quantitative analysis of the proteome remains a challenging task. phosphorylation of proteins is central to signal transduction pathways and plays an important role in plant defence against pathogens, although the immediate targets of kinases remain elusive. determining changes in the phosphoproteome during the defence response is a major goal in molecular plant pathology. in this first description of the novel mass tagging strategy (itraq appli ... | 2006 | 16850419 |
| formation of functional tat translocases from heterologous components. | the tat pathway transports folded proteins across the cytoplasmic membrane of bacteria and the thylakoid membrane of plants. in eschericha coli, tat transport requires the integral membrane proteins tata, tatb and tatc. in this study we have tested the ability of tat genes from the eubacterial species pseudomonas syringae, streptomyces coelicolor and aquifex aeolicus, to compensate for the absence of the cognate e. coli tat gene, and thus to form functional tat translocases with e. coli tat comp ... | 2006 | 16854235 |
| ectopic expression of the cotton non-symbiotic hemoglobin gene ghhbd1 triggers defense responses and increases disease tolerance in arabidopsis. | plant non-symbiotic hemoglobins (nshbs) play important roles in a variety of cellular processes. previous evidence from this laboratory indicates that the expression of a class 1 nshb gene (ghhb1) from cotton is induced in cotton roots challenged with the verticillium wilt fungus. the present study examined further the expression patterns of the ghhb1 gene in cotton plants and characterized its in vivo function through ectopic overexpression of the gene in arabidopsis thaliana. expression of ghh ... | 2006 | 16854938 |
| crystal structure of a type iii pantothenate kinase: insight into the mechanism of an essential coenzyme a biosynthetic enzyme universally distributed in bacteria. | pantothenate kinase (pank) catalyzes the first step in the five-step universal pathway of coenzyme a (coa) biosynthesis, a key transformation that generally also regulates the intracellular concentration of coa through feedback inhibition. a novel pank protein encoded by the gene coax was recently identified that is distinct from the previously characterized type i pank (exemplified by the escherichia coli coaa-encoded pank protein) and type ii eukaryotic panks and is not inhibited by coa or its ... | 2006 | 16855243 |
| identification and characterization of an azotobacter vinelandii type i secretion system responsible for export of the alge-type mannuronan c-5-epimerases. | alginate is a linear copolymer of beta-d-mannuronic acid and its c-5-epimer, alpha-l-guluronic acid. during biosynthesis, the polymer is first made as mannuronan, and various fractions of the monomers are then epimerized to guluronic acid by mannuronan c-5-epimerases. the azotobacter vinelandii genome encodes a family of seven extracellular such epimerases (alge1 to alge7) which display motifs characteristic for proteins secreted via a type i pathway. putative atpase-binding cassette regions fro ... | 2006 | 16855245 |
| a role for a flavin-containing mono-oxygenase in resistance against microbial pathogens in arabidopsis. | using activation tagging in the arabidopsis col-0 rps2-101c background, we identified a mutant (fmo1-3d) that showed virtually no symptoms after inoculation with virulent pseudomonas syringae pv. tomato dc3000 bacteria. the dominant, gain-of-function phenotype of the fmo1-3d mutant is due to over-expression of a class 3 flavin-containing mono-oxygenase (fmo). we recapitulated the fmo1-3d mutant phenotype in independent transgenic col-0 lines over-expressing the fmo1 cdna under the control of the ... | 2006 | 16856982 |
| identification of 17 pseudomonas aeruginosa srnas and prediction of srna-encoding genes in 10 diverse pathogens using the bioinformatic tool srnapredict2. | srnas are small, non-coding rna species that control numerous cellular processes. although it is widely accepted that srnas are encoded by most if not all bacteria, genome-wide annotations for srna-encoding genes have been conducted in only a few of the nearly 300 bacterial species sequenced to date. to facilitate the efficient annotation of bacterial genomes for srna-encoding genes, we developed a program, srnapredict2, that identifies putative srnas by searching for co-localization of genetic ... | 2006 | 16870723 |
| microbial colonization and competition on the marine alga ulva australis. | pseudalteromonas tunicata and roseobacter gallaeciensis are biofilm-forming marine bacteria that are often found in association with the surface of the green alga ulva australis. they are thought to benefit the plant host by producing inhibitory compounds that are active against common fouling organisms. we investigated factors that influence the ability of p. tunicata and r. gallaeciensis to attach to and colonize the plant surface and also the competitive interactions that occur between these ... | 2006 | 16885308 |
| the entry mechanism of membrane-containing phage bam35 infecting bacillus thuringiensis. | the temperate double-stranded dna bacteriophage bam35 infects gram-positive bacillus thuringiensis cells. bam35 has an icosahedral protein coat surrounding the viral membrane that encloses the linear 15-kbp dna genome. the protein coat of bam35 uses the same assembly principle as that of prd1, a lytic bacteriophage infecting gram-negative hosts. in this study, we dissected the process of bam35 entry into discrete steps: receptor binding, peptidoglycan penetration, and interaction with the plasma ... | 2006 | 16885461 |
| peroxidase-dependent apoplastic oxidative burst in arabidopsis required for pathogen resistance. | the oxidative burst is an early response to pathogen attack leading to the production of reactive oxygen species (ros) including hydrogen peroxide. two major mechanisms involving either nadph oxidases or peroxidases that may exist singly or in combination in different plant species have been proposed for the generation of ros. we identified an arabidopsis thaliana azide-sensitive but diphenylene iodonium-insensitive apoplastic oxidative burst that generates h(2)o(2) in response to a fusarium oxy ... | 2006 | 16889645 |
| the arabidopsis thaliana tir-nb-lrr r-protein, rpp1a; protein localization and constitutive activation of defence by truncated alleles in tobacco and arabidopsis. | specific recognition of hyaloperonospora parasitica isolate cala2 by arabidopsis thaliana ws-0 is mediated by the resistance gene rpp1a. transient expression of different truncations of rpp1a in tobacco leaves revealed that its tir-nb-arc portion is sufficient to induce an elicitor-independent cell death. in stable transgenic lines of arabidopsis, overexpression of the rpp1a tir-nb-arc domains (e12) using the 35s promoter leads to broad-spectrum resistance to virulent strains of h. parasitica an ... | 2006 | 16889647 |
| transgenic tobacco plants overexpressing chitinases of fungal origin show enhanced resistance to biotic and abiotic stress agents. | genes encoding defense-related proteins have been used to alter the resistance of plants to pathogens and other environmental challenges, but no single fungal gene overexpression has produced broad-spectrum stress resistance in transgenic lines. we have generated transgenic tobacco (nicotiana tabacum) lines that overexpress the endochitinases chit33 and chit42 from the mycoparasitic fungus trichoderma harzianum and have evaluated their tolerance to biotic and abiotic stress. both chit33 and chit ... | 2006 | 16891545 |
| characterization of the mrgrs locus of the opportunistic pathogen burkholderia pseudomallei: temperature regulates the expression of a two-component signal transduction system. | burkholderia pseudomallei is a saprophyte in tropical environments and an opportunistic human pathogen. this versatility requires a sensing mechanism that allows the bacterium to respond rapidly to altered environmental conditions. we characterized a two-component signal transduction locus from b. pseudomallei 204, mrgr and mrgs, encoding products with extensive homology with response regulators and histidine protein kinases of escherichia coli, bordetella pertussis, and vibrio cholerae. | 2006 | 16893462 |
| investigation of potential antibacterial properties of methanol extracts from fungus ganoderma applanatum. | in this study we searched for antibacterial compounds in methanol extracts of three layers (tube layer, context and cutis) of ganoderma applanatum fruit body against bacillus subtilis atcc 6051 as a gram-positive bacterium and escherichia coli atcc 25922 and pseudomonas syringae pv. syringae dpic 219 as gram-negative bacteria. we found antibacterial properties in all three layers only against gram-negative bacteria. the fractions were isolated and purified by thin layer chromatography (tlc) and ... | 2006 | 16899973 |