Publications

dual role of ohrr as a repressor and an activator in response to organic hydroperoxides in streptomyces coelicolor.	organic hydroperoxide resistance in bacteria is achieved primarily through reducing oxidized membrane lipids. the soil-inhabiting aerobic bacterium streptomyces coelicolor contains three paralogous genes for organic hydroperoxide resistance: ohra, ohrb, and ohrc. the ohra gene is transcribed divergently from ohrr, which encodes a putative regulator of marr family. both the ohra and ohrr genes were induced highly by various organic hydroperoxides. the ohra gene was induced through removal of repr ...	2007	17586628
estb-mediated hydrolysis of the siderophore triacetylfusarinine c optimizes iron uptake of aspergillus fumigatus.	aspergillus fumigatus excretes the fusarinine-type siderophore desferri-triacetylfusarinine c (df-tafc) to mobilize iron. df-tafc is a cyclic peptide consisting of three n(5)-cis-anhydromevalonyl-n(5)-hydroxy-n(2)-acetyl-l-ornithine residues linked by ester bonds; these linkages are in contrast to peptide linkages found for ferrichrome-type siderophores. subsequent to the binding of iron and uptake, triacetylfusarinine c (tafc) is hydrolyzed, the cleavage products are excreted, and the iron is t ...	2007	17586718
arabidopsis thaliana expresses multiple lines of defense to counterattack erwinia chrysanthemi.	many taxonomically diverse plant species are attacked by erwinia chrysanthemi, a member of the causal agents of soft-rotting diseases. symptom development is due to the collective action of pectin-degrading enzymes secreted by the bacterium through a type ii secretion system (t2ss). using arabidopsis thaliana as a susceptible host, we show that plants respond to e. chrysanthemi 3937 by expressing cell-wall reactions, production of an oxidative burst, and activation of salicylic acid (sa) and jas ...	2007	17601167
sucrose-mediated priming of plant defense responses and broad-spectrum disease resistance by overexpression of the maize pathogenesis-related prms protein in rice plants.	expression of pathogenesis-related (pr) genes is part of the plant's natural defense response against pathogen attack. the prms gene encodes a fungal-inducible pr protein from maize. here, we demonstrate that expression of prms in transgenic rice confers broad-spectrum protection against pathogens, including fungal (magnaporthe oryzae, fusarium verticillioides, and helminthosporium oryzae) and bacterial (erwinia chrysanthemi) pathogens. the prms-mediated disease resistance in rice plants is asso ...	2007	17601170
purification and three-dimensional electron microscopy structure of the neisseria meningitidis type iv pilus biogenesis protein pilg.	type iv pili are surface-exposed retractable fibers which play a key role in the pathogenesis of neisseria meningitidis and other gram-negative pathogens. pilg is an integral inner membrane protein and a component of the type iv pilus biogenesis system. it is related by sequence to the extensive gspf family of secretory proteins, which are involved in type ii secretion processes. pilg was overexpressed and purified from escherichia coli membranes by detergent extraction and metal ion affinity ch ...	2007	17616599
the linker region plays a key role in the adaptation to cold of the cellulase from an antarctic bacterium.	the psychrophilic cellulase, cel5g, from the antarctic bacterium pseudoalteromonas haloplanktis is composed of a catalytic module (cm) joined to a carbohydrate-binding module (cbm) by an unusually long, extended and flexible linker region (lr) containing three loops closed by three disulfide bridges. to evaluate the possible role of this region in cold adaptation, the lr was sequentially shortened by protein engineering, successively deleting one and two loops of this module, whereas the last di ...	2007	17635108
characterization of the erwinia chrysanthemi gan locus, involved in galactan catabolism.	beta-1,4-galactan is a major component of the ramified regions of pectin. analysis of the genome of the plant pathogenic bacteria erwinia chrysanthemi revealed the presence of a cluster of eight genes encoding proteins potentially involved in galactan utilization. the predicted transport system would comprise a specific porin ganl and an abc transporter made of four proteins, ganfgk(2). degradation of galactans would be catalyzed by the periplasmic 1,4-beta-endogalactanase gana, which released o ...	2007	17644603
gliding arc discharge in the potato pathogen erwinia carotovora subsp. atroseptica: mechanism of lethal action and effect on membrane-associated molecules.	gliding arc (glidarc) discharge is a physicochemical technique for decontamination at atmospheric pressure and ambient temperature. it leads to the destruction of bacterial phytopathogens responsible for important losses in industrial agriculture, namely, erwinia spp., without the formation of resistant forms. we investigated the effect of a novel optimized prototype allowing bacterial killing without lag time. this prototype also decreases the required duration of treatment by 50%. the study of ...	2007	17644644
characterization of the osmoprotectant transporter opuc from pseudomonas syringae and demonstration that cystathionine-beta-synthase domains are required for its osmoregulatory function.	the plant pathogen pseudomonas syringae may cope with osmotic stress on plants, in part, by importing osmoprotective compounds. in this study, we found that p. syringae pv. tomato strain dc3000 was distinct from most bacterial species in deriving greater osmoprotection from exogenous choline than from glycine betaine. this superior osmoprotection was correlated with a higher capacity for uptake of choline than for uptake of glycine betaine. of four putative osmoregulatory abc transporters in dc3 ...	2007	17660277
salicylic acid, yersiniabactin, and pyoverdin production by the model phytopathogen pseudomonas syringae pv. tomato dc3000: synthesis, regulation, and impact on tomato and arabidopsis host plants.	a genetically tractable model plant pathosystem, pseudomonas syringae pv. tomato dc3000 on tomato and arabidopsis thaliana hosts, was used to investigate the role of salicylic acid (sa) and iron acquisition via siderophores in bacterial virulence. pathogen-induced sa accumulation mediates defense in these plants, and dc3000 contains the genes required for the synthesis of sa, the sa-incorporated siderophore yersiniabactin (ybt), and the fluorescent siderophore pyoverdin (pvd). we found that dc30 ...	2007	17660289
cochlin in the eye: functional implications.	aqueous humor is actively produced in the ciliary epithelium of the anterior chamber and has important functions for the eye. under normal physiological conditions, the inflow and outflow of the aqueous humor are tightly regulated, but in the pathologic state this balance is lost. aqueous outflow involves structures of the anterior chamber and experiences most resistance at the level of the trabecular meshwork (tm) that acts as a filter. the modulation of the tm structure regulates the filter an ...	2007	17662637
a stress-induced rice (oryza sativa l.) beta-glucosidase represents a new subfamily of glycosyl hydrolase family 5 containing a fascin-like domain.	gh5bg, the cdna for a stress-induced gh5 (glycosyl hydrolase family 5) beta-glucosidase, was cloned from rice (oryza sativa l.) seedlings. the gh5bg cdna encodes a 510-amino-acid precursor protein that comprises 19 amino acids of prepeptide and 491 amino acids of mature protein. the protein was predicted to be extracellular. the mature protein is a member of a plant-specific subgroup of the gh5 exoglucanase subfamily that contains two major domains, a beta-1,3-exoglucanase-like domain and a fasc ...	2007	17705786
molecular basis of the activity of the phytopathogen pectin methylesterase.	we provide a mechanism for the activity of pectin methylesterase (pme), the enzyme that catalyses the essential first step in bacterial invasion of plant tissues. the complexes formed in the crystal using specifically methylated pectins, together with kinetic measurements of directed mutants, provide clear insights at atomic resolution into the specificity and the processive action of the erwinia chrysanthemi enzyme. product complexes provide additional snapshots along the reaction coordinate. w ...	2007	17717531
the heterologous expression of polysaccharidase-encoding genes with oenological relevance in saccharomyces cerevisiae.	the main objective of this study was to develop polysaccharide-degrading wine strains of saccharomyces cerevisiae, which are able to improve aspects of wine processing and clarification, as well as colour extraction and stabilization during winemaking.	2007	18045408
the dna nucleoid-associated protein fis co-ordinates the expression of the main virulence genes in the phytopathogenic bacterium erwinia chrysanthemi.	erwinia chrysanthemi strain 3937 is a necrotrophic bacterial plant pathogen. pectinolytic enzymes and, in particular, pectate lyases (pels) play a key role in soft rot symptoms but the efficient colonization of plants by e. chrysanthemi requires additional factors. these factors include the harpin hrpn, the cellulase cel5, proteases (prts), flagellar proteins and the sap system, involved in the detoxification of plant antimicrobial peptides. hrpn and flagellum are mostly involved in the early st ...	2007	18028311
integration of two essential virulence modulating signals at the erwinia chrysanthemi pel gene promoters: a role for fis in the growth-phase regulation.	production of the essential virulence factors, called pectate lyases (pels), in the phytopathogenic bacterium erwinia chrysanthemi is controlled by a complex regulation system and responds to various stimuli, such as the presence of pectin or plant extracts, growth phase, temperature and iron concentration. the presence of pectin and growth phase are the most important signals identified. eight regulators modulating the expression of the pel genes (encoding pels) have been characterized. these r ...	2007	18028312
the complete genome sequence and analysis of the epsilonproteobacterium arcobacter butzleri.	arcobacter butzleri is a member of the epsilon subdivision of the proteobacteria and a close taxonomic relative of established pathogens, such as campylobacter jejuni and helicobacter pylori. here we present the complete genome sequence of the human clinical isolate, a. butzleri strain rm4018.	2007	18159241
l-asparaginase from erwinia chrysanthemi 3937: cloning, expression and characterization.	bacterial l-asparaginases (l-asnases) catalyze the conversion of l-asparagine to l-aspartate and ammonia. in the present work, we report the cloning and expression of l-asparaginase from erwinia chrysanthemi 3937 (erl-asnase) in escherichia coli bl21(de3)plyss. the enzyme was purified to homogeneity in a single-step procedure involving cation exchange chromatography on an s-sepharose ff column. the enzymatic and structural properties of the recombinant enzyme were investigated and the kinetic pa ...	2007	16984804
the tolc homologue of brucella suis is involved in resistance to antimicrobial compounds and virulence.	brucella spp., like other pathogens, must cope with the environment of diverse host niches during the infection process. in doing this, pathogens evolved different type of transport systems to help them survive and disseminate within the host. members of the tolc family have been shown to be involved in the export of chemically diverse molecules ranging from large protein toxins to small toxic compounds. the role of proteins from the tolc family in brucella and other alpha-2-proteobacteria has b ...	2007	17088356
the tolc homologue of brucella suis is involved in resistance to antimicrobial compounds and virulence.	brucella spp., like other pathogens, must cope with the environment of diverse host niches during the infection process. in doing this, pathogens evolved different type of transport systems to help them survive and disseminate within the host. members of the tolc family have been shown to be involved in the export of chemically diverse molecules ranging from large protein toxins to small toxic compounds. the role of proteins from the tolc family in brucella and other alpha-2-proteobacteria has b ...	2007	17088356
tdea, a tolc-like protein required for toxin and drug export in aggregatibacter (actinobacillus) actinomycetemcomitans.	aggregatibacter actinomycetemcomitans is an oral bacterium that causes localized aggressive periodontitis (lap) and extra-oral infections such as sub-acute infective endocarditis. as part of its array of virulence factors, a. actinomycetemcomitans produces leukotoxin (ltxa), a member of the rtx family of toxins. ltxa kills human leukocytes and we have recently shown that the toxin is required for beta-hemolysis by a. actinomycetemcomitans on solid medium. in other rtx toxin-producing bacteria, a ...	2007	17116373
tdea, a tolc-like protein required for toxin and drug export in aggregatibacter (actinobacillus) actinomycetemcomitans.	aggregatibacter actinomycetemcomitans is an oral bacterium that causes localized aggressive periodontitis (lap) and extra-oral infections such as sub-acute infective endocarditis. as part of its array of virulence factors, a. actinomycetemcomitans produces leukotoxin (ltxa), a member of the rtx family of toxins. ltxa kills human leukocytes and we have recently shown that the toxin is required for beta-hemolysis by a. actinomycetemcomitans on solid medium. in other rtx toxin-producing bacteria, a ...	2007	17116373
high levels of expression of the iron-sulfur proteins phthalate dioxygenase and phthalate dioxygenase reductase in escherichia coli.	phthalate dioxygenase (pdo), a hexamer with one rieske-type [2fe-2s] and one fe (ii)-mononuclear center per monomer, and its reductase (pdr), which contains flavin mononucleotide and a plant-type ferredoxin [2fe-2s] center, are expressed by burkholderia cepacia at approximately 30mg of crude pdo and approximately 1mg of crude pdr per liter of cell culture when grown with phthalate as the main carbon source. a high level expression system in escherichia coli was developed for pdo and pdr. optimiz ...	2007	17049880
high levels of expression of the iron-sulfur proteins phthalate dioxygenase and phthalate dioxygenase reductase in escherichia coli.	phthalate dioxygenase (pdo), a hexamer with one rieske-type [2fe-2s] and one fe (ii)-mononuclear center per monomer, and its reductase (pdr), which contains flavin mononucleotide and a plant-type ferredoxin [2fe-2s] center, are expressed by burkholderia cepacia at approximately 30mg of crude pdo and approximately 1mg of crude pdr per liter of cell culture when grown with phthalate as the main carbon source. a high level expression system in escherichia coli was developed for pdo and pdr. optimiz ...	2007	17049880
modeling the onset of virulence in a pectinolytic bacterium.	building up from experimental knowledge of the regulatory network of the pel genes in the bacteria e. chrysanthemi, we propose for the first time a qualitative modeling of the infectious transition of this bacteria when it is hosted in a plant. we show that this infectious transition can be understood as the excitable dynamics of a metabolico-genetic network. our mathematical model can account for the main phases which are observed in the onset of the pathogenecity by erwinia chrysanthemi, namel ...	2007	17005207
differential role of ferritins in iron metabolism and virulence of the plant-pathogenic bacterium erwinia chrysanthemi 3937.	during infection, the phytopathogenic enterobacterium erwinia chrysanthemi has to cope with iron-limiting conditions and the production of reactive oxygen species by plant cells. previous studies have shown that a tight control of the bacterial intracellular iron content is necessary for full virulence. the e. chrysanthemi genome possesses two loci that could be devoted to iron storage: the bfr gene, encoding a heme-containing bacterioferritin, and the ftna gene, coding for a paradigmatic ferrit ...	2008	18165304
differential role of ferritins in iron metabolism and virulence of the plant-pathogenic bacterium erwinia chrysanthemi 3937.	during infection, the phytopathogenic enterobacterium erwinia chrysanthemi has to cope with iron-limiting conditions and the production of reactive oxygen species by plant cells. previous studies have shown that a tight control of the bacterial intracellular iron content is necessary for full virulence. the e. chrysanthemi genome possesses two loci that could be devoted to iron storage: the bfr gene, encoding a heme-containing bacterioferritin, and the ftna gene, coding for a paradigmatic ferrit ...	2008	18165304
a legionella pneumophila peptidyl-prolyl cis-trans isomerase present in culture supernatants is necessary for optimal growth at low temperatures.	several legionella pneumophila proteins were highly expressed in low-temperature supernatants. one of these proteins was the peptidyl-prolyl isomerase ppib. mutants lacking ppib exhibited reduced growth at 17 degrees c. since ppib lacked a signal sequence and was present in 17 degrees c supernatants of type ii and type iv secretion mutants, this protein may be secreted by a novel mechanism.	2008	18165359
a legionella pneumophila peptidyl-prolyl cis-trans isomerase present in culture supernatants is necessary for optimal growth at low temperatures.	several legionella pneumophila proteins were highly expressed in low-temperature supernatants. one of these proteins was the peptidyl-prolyl isomerase ppib. mutants lacking ppib exhibited reduced growth at 17 degrees c. since ppib lacked a signal sequence and was present in 17 degrees c supernatants of type ii and type iv secretion mutants, this protein may be secreted by a novel mechanism.	2008	18165359
the gaca global regulator is required for the appropriate expression of erwinia chrysanthemi 3937 pathogenicity genes during plant infection.	pathogenicity of the phytopathogenic enterobacterium erwinia chrysanthemi, the causal agent of soft rot disease on many plants, is a complex process involving several factors whose production is regulated by a complex, intertwined regulatory network. in this work we characterized the gaca regulator, member of the gacs-gaca two-component system, as a global regulator which is required for disease expression but not for bacterial multiplication in planta during the first stages of the plant infect ...	2008	18177376
role and regulation of iron-sulfur cluster biosynthesis genes in shigella flexneri virulence.	shigella flexneri, a causative agent of bacterial dysentery, possesses two predicted iron-sulfur cluster biosynthesis systems called suf and isc. s. flexneri strains containing deletion mutations in the entire suf operon (ur011) or the iscsua genes (ur022) were constructed. both mutants were defective in surviving exposure to oxidative stress. the suf mutant showed growth that was comparable to that of the parental strain in both iron-replete and iron-limiting media; however, the isc mutant show ...	2008	18195027
complicated catheter-associated urinary tract infections due to escherichia coli and proteus mirabilis.	catheter-associated urinary tract infections (cautis) represent the most common type of nosocomial infection and are a major health concern due to the complications and frequent recurrence. these infections are often caused by escherichia coli and proteus mirabilis. gram-negative bacterial species that cause cautis express a number of virulence factors associated with adhesion, motility, biofilm formation, immunoavoidance, and nutrient acquisition as well as factors that cause damage to the host ...	2008	18202436
the xanthomonas oryzae pv. oryzae phopq two-component system is required for avrxa21 activity, hrpg expression, and virulence.	the rice pathogen recognition receptor, xa21, confers resistance to xanthomonas oryzae pv. oryzae strains producing the type one system-secreted molecule, avrxa21. x. oryzae pv. oryzae requires a regulatory two-component system (tcs) called raxrh to regulate expression of eight rax (required for avrxa21 activity) genes and to sense population cell density. to identify other key components in this critical regulatory circuit, we assayed proteins expressed in a raxr gene knockout strain. this surv ...	2008	18203830
the iron stimulon of xylella fastidiosa includes genes for type iv pilus and colicin v-like bacteriocins.	xylella fastidiosa is the etiologic agent of a wide range of plant diseases, including citrus variegated chlorosis (cvc), a major threat to citrus industry. the genomes of several strains of this phytopathogen were completely sequenced, enabling large-scale functional studies. dna microarrays representing 2,608 (91.6%) coding sequences (cds) of x. fastidiosa cvc strain 9a5c were used to investigate transcript levels during growth with different iron availabilities. when treated with the iron che ...	2008	18223091
comparative secretome analysis suggests low plant cell wall degrading capacity in frankia symbionts.	frankia sp. strains, the nitrogen-fixing facultative endosymbionts of actinorhizal plants, have long been proposed to secrete hydrolytic enzymes such as cellulases, pectinases, and proteases that may contribute to plant root penetration and formation of symbiotic root nodules. these or other secreted proteins might logically be involved in the as yet unknown molecular interactions between frankia and their host plants. we compared the genome-based secretomes of three frankia strains representing ...	2008	18226217
identification of protein secretion systems and novel secreted proteins in rhizobium leguminosarum bv. viciae.	proteins secreted by bacteria play an important role in infection of eukaryotic hosts. rhizobia infect the roots of leguminous plants and establish a mutually beneficial symbiosis. proteins secreted during the infection process by some rhizobial strains can influence infection and modify the plant defence signalling pathways. the aim of this study was to systematically analyse protein secretion in the recently sequenced strain rhizobium leguminosarum bv. viciae 3841.	2008	18230162
structure of the minor pseudopilin epsh from the type 2 secretion system of vibrio cholerae.	many gram-negative bacteria use the multi-protein type ii secretion system (t2ss) to selectively translocate virulence factors from the periplasmic space into the extracellular environment. in vibrio cholerae the t2ss is called the extracellular protein secretion (eps) system,which translocates cholera toxin and several enzymes in their folded state across the outer membrane. five proteins of the t2ss, the pseudopilins, are thought to assemble into a pseudopilus, which may control the outer memb ...	2008	18241884
structure of the minor pseudopilin epsh from the type 2 secretion system of vibrio cholerae.	many gram-negative bacteria use the multi-protein type ii secretion system (t2ss) to selectively translocate virulence factors from the periplasmic space into the extracellular environment. in vibrio cholerae the t2ss is called the extracellular protein secretion (eps) system,which translocates cholera toxin and several enzymes in their folded state across the outer membrane. five proteins of the t2ss, the pseudopilins, are thought to assemble into a pseudopilus, which may control the outer memb ...	2008	18241884
biogenesis of fe/s proteins and pathogenicity: iscr plays a key role in allowing erwinia chrysanthemi to adapt to hostile conditions.	the erwinia chrysanthemi genome is predicted to encode three systems, nif, isc and suf, known to assist fe/s cluster biogenesis and the csdae cysteine desulphurase. single iscu, hsca and fdx mutants were found sensitive to paraquat and exhibited reduced virulence on both chicory leaves and arabidopsis thaliana. depletion of the whole isc system led to a pleiotropic phenotype, including sensitivity to both paraquat and 2,2'-dipyridyl, auxotrophies for branched-chain amino acids, thiamine, nicotin ...	2008	18284573
interactions between food-borne pathogens and protozoa isolated from lettuce and spinach.	the survival of salmonella enterica was recently shown to increase when the bacteria were sequestered in expelled food vacuoles (vesicles) of tetrahymena. because fresh produce is increasingly linked to outbreaks of enteric illness, the present investigation aimed to determine the prevalence of protozoa on spinach and lettuce and to examine their interactions with s. enterica, escherichia coli o157:h7, and listeria monocytogenes. glaucoma sp., colpoda steinii, and acanthamoeba palestinensis were ...	2008	18310421
x-ray structure of a prokaryotic pentameric ligand-gated ion channel.	pentameric ligand-gated ion channels (plgics) are key players in the early events of electrical signal transduction at chemical synapses. the family codes for a structurally conserved scaffold of channel proteins that open in response to the binding of neurotransmitter molecules. all proteins share a pentameric organization of identical or related subunits that consist of an extracellular ligand-binding domain followed by a transmembrane channel domain. the nicotinic acetylcholine receptor (nach ...	2008	18322461
expression, purification, crystallization and preliminary x-ray analysis of the polysaccharide lyase rb5312 from the marine planctomycete rhodopirellula baltica.	polysaccharide lyases belonging to family pl1 act on pectins. these anionic polymers are usually produced by terrestrial plants and therefore pectinolytic enzymes are not frequently observed in marine microorganisms. the protein rb5312 from the marine bacterium rhodopirellula baltica is distantly related to family pl1 pectate lyases, but its exact function is unclear. in this study, the expression and purification of a recombinant form of rb5312 are described. this protein was crystallized using ...	2008	18323615
pepper pectin methylesterase inhibitor protein capmei1 is required for antifungal activity, basal disease resistance and abiotic stress tolerance.	pectin is one of the main components of the plant cell wall that functions as the primary barrier against pathogens. among the extracellular pectinolytic enzymes, pectin methylesterase (pme) demethylesterifies pectin, which is secreted into the cell wall in a highly methylesterified form. here, we isolated and functionally characterized the pepper (capsicum annuum l.) gene capmei1, which encodes a pectin methylesterase inhibitor protein (pmei), in pepper leaves infected by xanthomonas campestris ...	2008	18327607
crystal structure of a functional dimer of the phoq sensor domain.	the phop-phoq two-component system is a well studied bacterial signaling system that regulates virulence and stress response. catalytic activity of the histidine kinase sensor protein phoq is activated by low extracellular concentrations of divalent cations such as mg2+, and subsequently the response regulator phop is activated in turn through a classic phosphotransfer pathway that is typical in such systems. the phoq sensor domains of enteric bacteria contain an acidic cluster of residues (eddd ...	2008	18348979
nitric oxide antagonizes the acid tolerance response that protects salmonella against innate gastric defenses.	reactive nitrogen species (rns) derived from dietary and salivary inorganic nitrogen oxides foment innate host defenses associated with the acidity of the stomach. the mechanisms by which these reactive species exert antimicrobial activity in the gastric lumen are, however, poorly understood.	2008	18350168
adhesion and retention of a bacterial phytopathogen erwinia chrysanthemi in biofilm-coated porous media.	the goal of this study is to investigate the impact of biofilm physical and biological properties on bacterial transport and deposition in porous media. experiments were performed in packed columns to examine the removal of erwinia chrysanthemi (ech3937), a phytopathogen, from the bulk fluid due to its attachmentto glass beads coated with pseudomonas aeruginosa biofilms. two isogenic p. aeruginosa strains, pao1 and pd0300, with different eps secretion capabilities and eps compositions, were used ...	2008	18350891
synthesis and biological activity of analogues of vanchrobactin, a siderophore from vibrio anguillarum serotype o2.	several analogues of vanchrobactin, a catechol siderophore isolated from the bacterial fish pathogen vibrio anguillarum serotype o2 strain rv22, have been synthesized. the biological evaluation of these novel compounds showed that most of them are active as siderophores, as determined by growth promotion assays using the producer strain, as well as v. anguillarum serotype o1, salmonella enterica, and erwinia chrysanthemi. these compounds also gave a positive chrome azurol-s (cas) test. on the ba ...	2008	18362969
characterization of the rnd-type multidrug efflux pump mexab-oprm of the plant pathogen pseudomonas syringae.	in gram-negative bacteria, transporters belonging to the rnd family are the transporters most relevant for resistance to antimicrobial compounds. in pseudomonas aeruginosa, a clinically important pathogen, the rnd-type pump mexab-oprm has been recognized as one of the major multidrug efflux systems. here, homologues of mexab-oprm in the plant pathogens pseudomonas syringae pv. phaseolicola 1448a, p. syringae pv. syringae b728a, and p. syringae pv. tomato dc3000 were identified, and mexab-oprm-de ...	2008	18390672
the crystal structure of pectate lyase peli from soft rot pathogen erwinia chrysanthemi in complex with its substrate.	the crystallographic structure of the family 3 polysaccharide lyase (pl-3) peli from erwinia chrysanthemi has been solved to 1.45 a resolution. it consists of an n-terminal domain harboring a fibronectin type iii fold linked to a catalytic domain displaying a parallel beta-helix topology. the n-terminal domain is located away from the active site and is not involved in the catalytic process. after secretion in planta, the two domains are separated by e. chrysanthemi proteases. this event turns o ...	2008	18430740
regulatory network controlling extracellular proteins in erwinia carotovora subsp. carotovora: flhdc, the master regulator of flagellar genes, activates rsmb regulatory rna production by affecting gaca and hexa (lrha) expression.	erwinia carotovora subsp. carotovora produces an array of extracellular proteins (i.e., exoproteins), including plant cell wall-degrading enzymes and harpin, an effector responsible for eliciting hypersensitive reaction. exoprotein genes are coregulated by the quorum-sensing signal, n-acyl homoserine lactone, plant signals, an assortment of transcriptional factors/regulators (gacs/a, expr1, expr2, kdgr, rpos, hexa, and rsmc) and posttranscriptional regulators (rsma, rsmb rna). rsmb rna productio ...	2008	18441056
chromosomal toxin-antitoxin systems may act as antiaddiction modules.	toxin-antitoxin (ta) systems are widespread among bacterial chromosomes and mobile genetic elements. although in plasmids ta systems have a clear role in their vertical inheritance by selectively killing plasmid-free daughter cells (postsegregational killing or addiction phenomenon), the physiological role of chromosomally encoded ones remains under debate. the assumption that chromosomally encoded ta systems are part of stress response networks and/or programmed cell death machinery has been ca ...	2008	18441063
genome sequence and rapid evolution of the rice pathogen xanthomonas oryzae pv. oryzae pxo99a.	xanthomonas oryzae pv. oryzae causes bacterial blight of rice (oryza sativa l.), a major disease that constrains production of this staple crop in many parts of the world. we report here on the complete genome sequence of strain pxo99a and its comparison to two previously sequenced strains, kacc10331 and maff311018, which are highly similar to one another.	2008	18452608
rhizobium cellulase celc2 is essential for primary symbiotic infection of legume host roots.	the rhizobia-legume, root-nodule symbiosis provides the most efficient source of biologically fixed ammonia fertilizer for agricultural crops. its development involves pathways of specificity, infectivity, and effectivity resulting from expressed traits of the bacterium and host plant. a key event of the infection process required for development of this root-nodule symbiosis is a highly localized, complete erosion of the plant cell wall through which the bacterial symbiont penetrates to establi ...	2008	18458328
structural determinants of ca2+ permeability and conduction in the human 5-hydroxytryptamine type 3a receptor.	cation-selective cysteine (cys)-loop transmitter-gated ion channels provide an important pathway for ca2+ entry into neurones. we examined the influence on ca2+ permeation of amino acids located at intra- and extracellular ends of the conduction pathway of the human 5-hydroxytryptamine type 3a (5-ht3a) receptor. mutation of cytoplasmic arginine residues 432, 436, and 440 to glutamine, aspartate, and alanine (the aligned residues of the human 5-ht3b subunit (yielding 5-ht3a(qda)) increased pca/pc ...	2008	18474595
the major facilitator superfamily-type transporter ymfe and the multidrug-efflux activator mta mediate bacillibactin secretion in bacillus subtilis.	high-affinity iron acquisition in bacillus subtilis is mediated via the bacillibactin catechole siderophore pathway. three of the four essential pathway steps, bacillibactin synthesis, fe-bacillibactin uptake, and fe-bacillibactin hydrolysis have been characterized previously. the functional and regulatory components for bacillibactin secretion, the second step of the siderophore pathway, remained unknown. in this study, the screening of a b. subtilis exporter mutant library led to the identific ...	2008	18502870
the phoq histidine kinases of salmonella and pseudomonas spp. are structurally and functionally different: evidence that ph and antimicrobial peptide sensing contribute to mammalian pathogenesis.	the phoq sensor kinase is essential for salmonella typhimurium virulence for animals, and a homologue exists in the environmental organism and opportunistic pathogen pseudomonas aeruginosa. s. typhimurium phoq (st-phoq) is repressed by millimolar concentrations of divalent cations and activated by antimicrobial peptides and at acidic ph. st-phoq has a periplasmic per-arnt-sim domain, a fold commonly employed for ligand binding. however, substrate binding is instead accomplished by an acidic patc ...	2008	18532985
structural biology of pectin degradation by enterobacteriaceae.	summary: pectin is a structural polysaccharide that is integral for the stability of plant cell walls. during soft rot infection, secreted virulence factors from pectinolytic bacteria such as erwinia spp. degrade pectin, resulting in characteristic plant cell necrosis and tissue maceration. catabolism of pectin and its breakdown products by pectinolytic bacteria occurs within distinct cellular environments. this process initiates outside the cell, continues within the periplasmic space, and culm ...	2008	18535148
insights into plant cell wall degradation from the genome sequence of the soil bacterium cellvibrio japonicus.	the plant cell wall, which consists of a highly complex array of interconnecting polysaccharides, is the most abundant source of organic carbon in the biosphere. microorganisms that degrade the plant cell wall synthesize an extensive portfolio of hydrolytic enzymes that display highly complex molecular architectures. to unravel the intricate repertoire of plant cell wall-degrading enzymes synthesized by the saprophytic soil bacterium cellvibrio japonicus, we sequenced and analyzed its genome, wh ...	2008	18556790
dsba plays a critical and multifaceted role in the production of secreted virulence factors by the phytopathogen erwinia carotovora subsp. atroseptica.	erwinia carotovora subsp. atroseptica is an enterobacterial phytopathogen causing economically significant soft rot disease. pathogenesis is mediated by multiple secreted virulence factors, many of which are secreted by the type ii (out) secretion system. dsba catalyzes the introduction of disulfide bonds into periplasmic and secreted proteins. in this study, the extracellular proteome (secretome) of wild type e. carotovora subsp. atroseptica scri1043, and dsba and out mutants, was analyzed by s ...	2008	18562317
quorum sensing coordinates brute force and stealth modes of infection in the plant pathogen pectobacterium atrosepticum.	quorum sensing (qs) in vitro controls production of plant cell wall degrading enzymes (pcwdes) and other virulence factors in the soft rotting enterobacterial plant pathogen pectobacterium atrosepticum (pba). here, we demonstrate the genome-wide regulatory role of qs in vivo during the pba-potato interaction, using a pba-specific microarray. we show that 26% of the pba genome exhibited differential transcription in a qs (expi-) mutant, compared to the wild-type, suggesting that qs may make a gre ...	2008	18566662
the compatible-solute-binding protein opuac from bacillus subtilis: ligand binding, site-directed mutagenesis, and crystallographic studies.	in the soil bacterium bacillus subtilis, five transport systems work in concert to mediate the import of various compatible solutes that counteract the deleterious effects of increases in the osmolarity of the environment. among these five systems, the abc transporter opua, which catalyzes the import of glycine betaine and proline betaine, has been studied in detail in the past. here, we demonstrate that opua is capable of importing the sulfobetaine dimethylsulfonioacetate (dmsa). since opua is ...	2008	18567662
[genetic and molecular characters of toxin producing erwinia chrysanthemi pv. zeae].	bacterial foot rot, caused by erwinia chrysanthemi pv. zeae, is one of the most important diseases in rice. genetic and molecular characters of toxin producting for erwinia chrysanthemi pv. zeae were conducted in this paper.	2008	18590228
comparative analysis of the glg operons of pectobacterium chrysanthemi py35 and other prokaryotes.	a chromosomal region of pectobacterium chrysanthemi py35 that contains of genes for glycogen synthesis was isolated from a cosmid library. the operon consists of glycogen branching enzyme (glgb), glycogen debranching enzyme (glgx), adp-glucose pyrophosphorylase (glgc), glycogen synthase (glga), and glycogen phosphorylase (glgp) genes. gene organization is similar to that of escherichia coli. the purified adp-glucose pyrophosphorylase (glgc) was activated by fructose 1,6-bisphosphate and inhibite ...	2008	18594899
bacterial apbc can bind and effectively transfer iron-sulfur clusters.	the metabolism of iron-sulfur ([fe-s]) clusters requires a complex set of machinery that is still being defined. mutants of salmonella enterica lacking apbc have nutritional and biochemical properties indicative of defects in [fe-s] cluster metabolism. apbc is a 40.8 kda homodimeric atpase and as purified contains little iron and no acid-labile sulfide. an [fe-s] cluster was reconstituted on apbc, generating a protein that bound 2 mol of fe and 2 mol of s (2-) per apbc monomer and had a uv-visib ...	2008	18616280
in vitro multimerization and membrane insertion of bacterial outer membrane secretin puld.	synthesis of the klebsiella oxytoca outer membrane secretin puld, or its membrane-associated core domain, in a liposome-supplemented escherichia coli in vitro transcription-translation system resulted in the formation of multimers that appeared as typical dodecameric secretin rings when examined by negative-stain electron microscopy. cryo-electron microscopy of unstained liposomes and differential extraction by urea indicated that the secretin particles were inserted into the liposome membranes. ...	2008	18616949
dynamic regulation of gaca in type iii secretion, pectinase gene expression, pellicle formation, and pathogenicity of dickeya dadantii (erwinia chrysanthemi 3937).	dickeya dadantii (erwinia chrysanthemi 3937) secretes exoenzymes, including pectin-degrading enzymes, leading to the loss of structural integrity of plant cell walls. a type iii secretion system (t3ss) is essential for full virulence of this bacterium within plant hosts. the gacs/gaca two-component signal transduction system participates in important biological roles in several gram-negative bacteria. in this study, a gaca deletion mutant (ech137) of d. dadantii was constructed to investigate th ...	2008	18052890
evolution of ghf5 endoglucanase gene structure in plant-parasitic nematodes: no evidence for an early domain shuffling event.	endo-1,4-beta-glucanases or cellulases from the glycosyl hydrolase family 5 (ghf5) have been found in numerous bacteria and fungi, and recently also in higher eukaryotes, particularly in plant-parasitic nematodes (ppn). the origin of these genes has been attributed to horizontal gene transfer from bacteria, although there still is a lot of uncertainty about the origin and structure of the ancestral ghf5 ppn endoglucanase. it is not clear whether this ancestral endoglucanase consisted of the whol ...	2008	18980666
siderophore-controlled iron assimilation in the enterobacterium erwinia chrysanthemi: evidence for the involvement of bacterioferritin and the suf iron-sulfur cluster assembly machinery.	the intracellular fate of iron acquired by bacteria during siderophore-mediated assimilation is poorly understood. we investigated this question in the pathogenic enterobacterium erwinia chrysanthemi. this bacterium produces two siderophores, chrysobactin and achromobactin, during plant infection. we analyzed the distribution of iron into cytosolic proteins in bacterial cells supplied with 59fe-chrysobactin using native gel electrophoresis. a parental strain and mutants deficient in bacterioferr ...	2008	18990691
purification, crystallization and data collection of pectobacterium chrysanthemi acsd, a type a siderophore synthetase.	acsd, a type a siderophore synthetase with a molecular weight of 71 140 da from pectobacterium chrysanthemi, has been expressed, purified and crystallized at 293 k. the protein crystallized in the primitive orthorhombic space group p2(1)2(1)2(1), with unit-cell parameters a = 80.3, b = 95.7, c = 161.1 a, alpha = beta = gamma = 90 degrees . systematic absences were consistent with space group p2(1)2(1)2(1). a complete data set has been collected to 2.25 a resolution on bm14 at the esrf. considera ...	2008	18997340
acquisition and evolution of plant pathogenesis-associated gene clusters and candidate determinants of tissue-specificity in xanthomonas.	xanthomonas is a large genus of plant-associated and plant-pathogenic bacteria. collectively, members cause diseases on over 392 plant species. individually, they exhibit marked host- and tissue-specificity. the determinants of this specificity are unknown.	2008	19043590
plant lesions promote the rapid multiplication of escherichia coli o157:h7 on postharvest lettuce.	several outbreaks of escherichia coli o157:h7 infections have been associated with minimally processed leafy vegetables in the united states. harvesting and processing cause plant tissue damage. in order to assess the role of plant tissue damage in the contamination of leafy greens with e. coli o157:h7, the effect of mechanical, physiological, and plant disease-induced lesions on the growth of this pathogen on postharvest romaine lettuce was investigated. within only 4 h after inoculation, the p ...	2008	18641153
global gene expression profiles suggest an important role for nutrient acquisition in early pathogenesis in a plant model of pseudomonas aeruginosa infection.	although pseudomonas aeruginosa is an opportunistic pathogen that does not often naturally infect alternate hosts, such as plants, the plant-p. aeruginosa model has become a widely recognized system for identifying new virulence determinants and studying the pathogenesis of the organism. here, we examine how both host factors and p. aeruginosa pao1 gene expression are affected in planta after infiltration into incompatible and compatible cultivars of tobacco (nicotiana tabacum l.). n. tabacum ha ...	2008	18641163
complete genome sequence of the n2-fixing broad host range endophyte klebsiella pneumoniae 342 and virulence predictions verified in mice.	we report here the sequencing and analysis of the genome of the nitrogen-fixing endophyte, klebsiella pneumoniae 342. although k. pneumoniae 342 is a member of the enteric bacteria, it serves as a model for studies of endophytic, plant-bacterial associations due to its efficient colonization of plant tissues (including maize and wheat, two of the most important crops in the world), while maintaining a mutualistic relationship that encompasses supplying organic nitrogen to the host plant. genomic ...	2008	18654632
spx mediates oxidative stress regulation of the methionine sulfoxide reductases operon in bacillus subtilis.	all aerobically grown living cells are exposed to oxidative damage by reactive oxygen species (ros). a major damage by ros to proteins is caused by covalent modifications of methionine residues giving methionine sulfoxide (met-so). methionine sulfoxide reductases are enzymes able to regenerate methionine and restore protein function after oxidative damage.	2008	18662407
characterization of chromosomal regions conserved in yersinia pseudotuberculosis and lost by yersinia pestis.	the transformation of the enteropathogenic bacterium yersinia pseudotuberculosis into the plague bacillus, yersinia pestis, has been accompanied by extensive genetic loss. this study focused on chromosomal regions conserved in y. pseudotuberculosis and lost during its transformation into y. pestis. an extensive pcr screening of 78 strains of the two species identified five regions (r1 to r5) and four open reading frames (orfs; orf1 to orf4) that were conserved in y. pseudotuberculosis and absent ...	2008	18678673
expression, purification and crystallization of helicobacter pylori l-asparaginase.	the l-asparaginases from escherichia coli and erwinia chrysanthemi are effective drugs that have been used in the treatment of acute childhood lymphoblastic leukaemia for over 30 years. however, despite their therapeutic potential, they can cause serious side effects as a consequence of their intrinsic glutaminase activity, which leads to l-glutamine depletion in the blood. consequently, new asparaginases with low glutaminase activity, fewer side effects and high activity towards l-asparagine ar ...	2008	18678946
crystallization and preliminary crystallographic analysis of mannosyl-3-phosphoglycerate synthase from rubrobacter xylanophilus.	rubrobacter xylanophilus is the only gram-positive bacterium known to synthesize the compatible solute mannosylglycerate (mg), which is commonly found in hyperthermophilic archaea and some thermophilic bacteria. unlike the salt-dependent pattern of accumulation observed in (hyper)thermophiles, in r. xylanophilus mg accumulates constitutively. the synthesis of mg in r. xylanophilus was tracked from gdp-mannose and 3-phosphoglycerate, but the genome sequence of the organism failed to reveal any of ...	2008	18678952
type iii secretion system genes of dickeya dadantii 3937 are induced by plant phenolic acids.	dickeya dadantii is a broad-host range phytopathogen. d. dadantii 3937 (ech3937) possesses a type iii secretion system (t3ss), a major virulence factor secretion system in many gram-negative pathogens of plants and animals. in ech3937, the t3ss is regulated by two major regulatory pathways, hrpx/hrpy-hrps-hrpl and gacs/gaca-rsmb-rsma pathways. although the plant apoplast environment, low ph, low temperature, and absence of complex nitrogen sources in media have been associated with the induction ...	2008	18698421
abscisic acid deficiency leads to rapid activation of tomato defence responses upon infection with erwinia chrysanthemi.	in addition to the important role of abscisic acid (aba) in abiotic stress signalling, basal and high aba levels appear to have a negative effect on disease resistance. using the aba-deficient sitiens tomato (solanum lycopersicum) mutant and different application methods of exogenous aba, we demonstrated the influence of this plant hormone on disease progression of erwinia chrysanthemi. this necrotrophic plant pathogenic bacterium is responsible for soft rot disease on many plant species, causin ...	2008	18705880
identification of lacto-n-biose i phosphorylase from vibrio vulnificus cmcp6.	a beta-1,3-galactosyl-n-acetylhexosamine phosphorylase (galglynacp) homolog gene was cloned from vibrio vulnificus cmcp6. in synthetic reactions, the recombinant enzyme acted only with glcnac and galnac as acceptors in the presence of alpha-d-galactose-1-phosphate as a donor to form lacto-n-biose i (lnb) (galbeta1 --> 3glcnac) and galacto-n-biose (gnb) (galbeta1 --> 3galnac), respectively. glcnac was a much better acceptor than galnac. the enzyme also phosphorolysed lnb faster than it phosphorol ...	2008	18723650
characterization of tolc efflux pump proteins from pasteurella multocida.	two tolc homologs, pm0527 and pm1980, were identified for pasteurella multocida. a pm0527 mutant displayed increased susceptibility to a range of chemicals, including rifampin (512-fold) and acridine orange (128-fold). a pm1980 mutant showed increased susceptibility to rifampin, ceftazidime, and vancomycin.	2008	18725450
pecs is a global regulator of the symptomatic phase in the phytopathogenic bacterium erwinia chrysanthemi 3937.	pathogenicity of the enterobacterium erwinia chrysanthemi (dickeya dadantii), the causative agent of soft-rot disease in many plants, is a complex process involving several factors whose production is subject to temporal regulation during infection. pecs is a transcriptional regulator that controls production of various virulence factors. here, we used microarray analysis to define the pecs regulon and demonstrated that pecs notably regulates a wide range of genes that could be linked to pathoge ...	2008	18790868
iron(iii) uptake and release by chrysobactin, a siderophore of the phytophatogenic bacterium erwinia chrysanthemi.	the plant pathogenic enterobacterium erwinia chrysanthemi causes important soft-rot disease on a wide range of plants including vegetables and ornamentals of economic importance. it produces a major mono(catecholate) siderophore, chrysobactin (alpha-n-(2,3-dihydroxybenzoyl)-d-lysyl-l-serine). to unravel the role of chrysobactin in the virulence of e. chrysanthemi, its iron(iii) coordination properties were thus investigated in aqueous solutions using electrospray ionization mass spectrometric, p ...	2008	18803373
the missing link: bordetella petrii is endowed with both the metabolic versatility of environmental bacteria and virulence traits of pathogenic bordetellae.	bordetella petrii is the only environmental species hitherto found among the otherwise host-restricted and pathogenic members of the genus bordetella. phylogenetically, it connects the pathogenic bordetellae and environmental bacteria of the genera achromobacter and alcaligenes, which are opportunistic pathogens. b. petrii strains have been isolated from very different environmental niches, including river sediment, polluted soil, marine sponges and a grass root. recently, clinical isolates asso ...	2008	18826580
the flagellar sigma factor flia is required for dickeya dadantii virulence.	the genome sequence of the enterobacteriaceae phytopathogen dickeya dadantii (formerly erwinia chrysanthemi) revealed homologs of genes required for a complete flagellar secretion system and one flagellin gene. we found that d. dadantii was able to swim and swarm but that ability to swarm was dependent upon both growth media and temperature. mutation of the d. dadantii flia gene was pleiotropic, with the alternate sigma factor required for flagella production and development of disease symptoms ...	2008	18842093
analysis of the laci family regulators of erwinia chrysanthemi 3937, involvement in the bacterial phytopathogenicity.	analysis of the regulators of the laci family was performed in order to identify those potentially involved in pathogenicity of erwinia chrysanthemi (dickeya dadantii). among the 18 members of the laci family, the function of 11 members is either known or predicted and only 7 members have, as yet, no proposed function. inactivation of these seven genes, called lfar, lfbr, lfcr, lfdr, lfer, lffr, and lfgr, demonstrated that four of them are important for plant infection. the lfar and lfcr mutants ...	2008	18842096
in silico models for the human alpha4beta2 nicotinic acetylcholine receptor.	the neuronal alpha4beta2 nicotinic acetylcholine receptor (nachr) is one of the most widely expressed nachr subtypes in the brain. its subunits have high sequence identity (54 and 46% for alpha4 and beta2, respectively) with alpha and beta subunits in torpedo nachr. using the known structure of the torpedo nachr as a template, the closed-channel structure of the alpha4beta2 nachr was constructed through homology modeling. normal-mode analysis was performed on this closed structure and the result ...	2008	18847252
the impact of o(2) on the fe-s cluster biogenesis requirements of escherichia coli fnr.	in this study, the functions of two established fe-s cluster biogenesis pathways, isc (iron-sulfur cluster) and suf (sulfur mobilization), under aerobic and anaerobic growth conditions were compared by measuring the activity of the escherichia coli global anaerobic regulator fnr. a [4fe-4s] cluster is required for fnr activity under anaerobic conditions. an assay of the expression of fnr-dependent promoters in strains containing various deletions of the iscsuahscbafdx operon revealed that, under ...	2008	18938178
quorum sensing primes the oxidative stress response in the insect endosymbiont, sodalis glossinidius.	sodalis glossinidius, a maternally transmitted bacterial endosymbiont of tsetse flies (glossina spp.), uses an acylated homoserine lactone (ahl)-based quorum sensing system to modulate gene expression in accordance with bacterial cell density. the s. glossinidius quorum sensing system relies on the function of two regulatory proteins; sogi (a luxi homolog) synthesizes a signaling molecule, characterized as n-(3-oxohexanoyl) homoserine lactone (ohhl), and sogr1 (a luxr homolog) interacts with ohh ...	2008	18958153
enteropathogen resource integration center (eric): bioinformatics support for research on biodefense-relevant enterobacteria.	eric, the enteropathogen resource integration center (www.ericbrc.org), is a new web portal serving as a rich source of information about enterobacteria on the niaid established list of select agents related to biodefense-diarrheagenic escherichia coli, shigella spp., salmonella spp., yersinia enterocolitica and yersinia pestis. more than 30 genomes have been completely sequenced, many more exist in draft form and additional projects are underway. these organisms are increasingly the focus of st ...	2008	17999997
enteropathogen resource integration center (eric): bioinformatics support for research on biodefense-relevant enterobacteria.	eric, the enteropathogen resource integration center (www.ericbrc.org), is a new web portal serving as a rich source of information about enterobacteria on the niaid established list of select agents related to biodefense-diarrheagenic escherichia coli, shigella spp., salmonella spp., yersinia enterocolitica and yersinia pestis. more than 30 genomes have been completely sequenced, many more exist in draft form and additional projects are underway. these organisms are increasingly the focus of st ...	2008	17999997
the crystal structure of a binary complex of two pseudopilins: epsi and epsj from the type 2 secretion system of vibrio vulnificus.	type ii secretion systems (t2ss) translocate virulence factors from the periplasmic space of many pathogenic bacteria into the extracellular environment. the t2ss of vibrio cholerae and related species is called the extracellular protein secretion (eps) system that consists of a core of multiple copies of 11 different proteins. the pseudopilins, epsg, epsh, epsi, epsj and epsk, are five t2ss proteins that are thought to assemble into a pseudopilus, which is assumed to interact with the outer mem ...	2008	18022192
the crystal structure of a binary complex of two pseudopilins: epsi and epsj from the type 2 secretion system of vibrio vulnificus.	type ii secretion systems (t2ss) translocate virulence factors from the periplasmic space of many pathogenic bacteria into the extracellular environment. the t2ss of vibrio cholerae and related species is called the extracellular protein secretion (eps) system that consists of a core of multiple copies of 11 different proteins. the pseudopilins, epsg, epsh, epsi, epsj and epsk, are five t2ss proteins that are thought to assemble into a pseudopilus, which is assumed to interact with the outer mem ...	2008	18022192
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
cta4 transcription factor mediates induction of nitrosative stress response in candida albicans.	this work has identified regulatory elements in the major fungal pathogen candida albicans that enable response to nitrosative stress. nitric oxide (no) is generated by macrophages of the host immune system and commensal bacteria, and the ability to resist its toxicity is one adaptation that promotes survival of c. albicans inside the human body. exposing c. albicans to no induces upregulation of the flavohemoglobin yhb1p. this protein confers protection by enzymatically converting no to harmles ...	2008	18083829
cta4 transcription factor mediates induction of nitrosative stress response in candida albicans.	this work has identified regulatory elements in the major fungal pathogen candida albicans that enable response to nitrosative stress. nitric oxide (no) is generated by macrophages of the host immune system and commensal bacteria, and the ability to resist its toxicity is one adaptation that promotes survival of c. albicans inside the human body. exposing c. albicans to no induces upregulation of the flavohemoglobin yhb1p. this protein confers protection by enzymatically converting no to harmles ...	2008	18083829
the intracellular pathogen rhodococcus equi produces a catecholate siderophore required for saprophytic growth.	little is known about the iron acquisition systems of the soilborne facultative intracellular pathogen rhodococcus equi. we previously reported that expression of iupabc, encoding a putative siderophore abc transporter system, is iron regulated and required for growth at low iron concentrations. here we show that disruption of iupa leads to the concomitant accumulation of catecholates and a chromophore with absorption maxima at 341 and 528 nm during growth under iron-replete conditions. in contr ...	2008	18156254
the intracellular pathogen rhodococcus equi produces a catecholate siderophore required for saprophytic growth.	little is known about the iron acquisition systems of the soilborne facultative intracellular pathogen rhodococcus equi. we previously reported that expression of iupabc, encoding a putative siderophore abc transporter system, is iron regulated and required for growth at low iron concentrations. here we show that disruption of iupa leads to the concomitant accumulation of catecholates and a chromophore with absorption maxima at 341 and 528 nm during growth under iron-replete conditions. in contr ...	2008	18156254
pseudomonas syringae bett is a low-affinity choline transporter that is responsible for superior osmoprotection by choline over glycine betaine.	the plant pathogen pseudomonas syringae derives better osmoprotection from choline than from glycine betaine, unlike most bacteria that have been characterized. in this report, we identified a betaine/carnitine/choline family transporter (bcct) in p. syringae pv. tomato strain dc3000 that mediates the transport of choline and acetylcholine. this transporter has a particularly low affinity (k(m) of 876 microm) and high capacity (v(max) of 80 nmol/min/mg of protein) for choline transport relative ...	2008	18156257