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the influence of the accessory genome on bacterial pathogen evolution.bacterial pathogens exhibit significant variation in their genomic content of virulence factors. this reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type iii protein secretion effectors and hosts encoding ever more sophisticated immune systems. the pathogens' frequent expo ...201122016845
proteomics and functional analyses of pepper abscisic acid-responsive 1 (abr1), which is involved in cell death and defense signaling.abscisic acid (aba) is a key regulator of plant growth and development, as well as plant defense responses. a high-throughput in planta proteome screen identified the pepper (capsicum annuum) gram (for glucosyltransferases, rab-like gtpase activators, and myotubularins) domain-containing aba-responsive1 (abr1), which is highly induced by infection with avirulent xanthomonas campestris pv vesicatoria and also by treatment with aba. the gram domain is essential for the cell death response and for ...201121335377
elucidation of the regulon and cis-acting regulatory element of hrpb, the arac-type regulator of a plant pathogen-like type iii secretion system in burkholderia pseudomallei.the human pathogen burkholderia pseudomallei possesses multiple type iii secretion system (t3ss) gene clusters. one of these, the b. pseudomallei t3ss2 (t3ss2(bp)) gene cluster, which apparently plays no role in animal virulence, is also found in six additional burkholderia spp. and is very similar to t3sss found in phytopathogenic xanthomonas spp. and ralstonia solanacearum. the t3ss2(bp) gene cluster also encodes an arac-type regulatory protein (hrpb(bp)) that is an ortholog of hrpb, the maste ...201121335458
levantilides a and b, 20-membered macrolides from a micromonospora strain isolated from the mediterranean deep sea sediment.two new 20-membered macrolides, levantilide a and b, were isolated from the micromonospora strain m71-a77. strain m71-a77 was recovered from an eastern mediterranean deep-sea sediment sample and revealed to produce the levantilides under in situ salinity of 38.6 ‰. the chemical structures of the levantilides were elucidated on the basis of different one- and two- dimensional nmr experiments. levantilide a exhibits a moderate antiproliferative activity against several tumor cell lines.201121339949
extracellular streptomyces vesicles: amphorae for survival and defence.blue-pigmented exudates arise as droplets on sporulated lawns of streptomyces coelicolor m110 grown on agar plates. our electron microscopical and biochemical studies suggest that droplets contain densely packed vesicles with large assemblies of different protein types and/or the polyketide antibiotic actinorhodin. frozen-hydrated vesicles were unilamellar with a typical bilayer membrane, and ranged from 80 to 400 nm in diameter with a preferred width of 150-300 nm. by means of cryo-electron tom ...201121342473
analysis of the borrelia burgdorferi cyclic-di-gmp-binding protein plza reveals a role in motility and virulence.the cyclic-dimeric-gmp (c-di-gmp)-binding protein pilz has been implicated in bacterial motility and pathogenesis. although bb0733 (plza), the only pilz domain-containing protein in borrelia burgdorferi, was reported to bind c-di-gmp, neither its role in motility or virulence nor it's affinity for c-di-gmp has been reported. we determined that plza specifically binds c-di-gmp with high affinity (dissociation constant [k(d)], 1.25 µm), consistent with k(d) values reported for c-di-gmp-binding pro ...201121357718
expression, purification and biochemical characterization of gumi, a monotopic membrane gdp-mannose:glycolipid 4-{beta}-d-mannosyltransferase from xanthomonas campestris pv. campestris.we describe the first biochemical characterization of the gumi gene product, an essential protein for xanthan polysaccharide synthesis. cellular fractionation experiments reveal the presence of a protein associated with the membrane fraction, even in the absence of the other proteins responsible for the synthesis of glycolipid intermediates and the proteins involved in the polymerization and transport of the xanthan chains. by alkaline buffer extraction and detergent phase partitioning, gumi was ...201121367879
graded expression of zinc-responsive genes through two regulatory zinc-binding sites in zur.zinc is one of the essential transition metals in cells. excess or lack of zinc is detrimental, and cells exploit highly sensitive zinc-binding regulators to achieve homeostasis. in this article, we present a crystal structure of active zur from streptomyces coelicolor with three zinc-binding sites (c-, m-, and d-sites). mutations of the three sites differentially affected sporulation and transcription of target genes, such that c- and m-site mutations inhibited sporulation and derepressed all t ...201121383173
delicate conformational changes of a protein in the crp family lead to dramatic functional changes via binding of an alternate secondary messenger molecule.clp (c-amp receptor protein like protein) from the plant pathogen xanthomonas campestris (xc) is a moderately strong c-di-gmp binder. after binding with c-di-gmp, xcclp is dissociated from dna, thus changing the expression profile of approximately 300 downstream genes, many of which are involved in the pathogenicity of xc. to better understand the intricacies of this interesting regulation mechanism, a crystal structure of xcclp has been determined to a resolution of 2.28 +à. this, in conjunctio ...201121383542
interaction of common bacterial blight bacteria with disease resistance quantitative trait loci in common bean.common bacterial blight (cbb) of common bean (phaseolus vulgaris l.) is caused by xanthomonas campestris pv. phaseoli and x. fuscans subsp. fuscans, and is the most important bacterial disease of this crop in many regions of the world. in 2005 and 2006, dark red kidney bean fields in a major bean-growing region in central wisconsin were surveyed for cbb incidence and representative symptomatic leaves collected. xanthomonad-like bacteria were isolated from these leaves and characterized based upo ...201121391823
comparative genomics reveals diversity among xanthomonads infecting tomato and pepper.bacterial spot of tomato and pepper is caused by four xanthomonas species and is a major plant disease in warm humid climates. the four species are distinct from each other based on physiological and molecular characteristics. the genome sequence of strain 85-10, a member of one of the species, xanthomonas euvesicatoria (xcv) has been previously reported. to determine the relationship of the four species at the genome level and to investigate the molecular basis of their virulence and differing ...201121396108
antibacterial peptides from plants: what they are and how they probably work.plant antibacterial peptides have been isolated from a wide variety of species. they consist of several protein groups with different features, such as the overall charge of the molecule, the content of disulphide bonds, and structural stability under environmental stress. although the three-dimensional structures of several classes of plant peptides are well determined, the mechanism of action of some of these molecules is still not well defined. however, further studies may provide new evidenc ...201121403856
structure-function analysis of the hrpb2-hrcu interaction in the xanthomonas citri type iii secretion system.bacterial type iii secretion systems deliver protein virulence factors to host cells. here we characterize the interaction between hrpb2, a small protein secreted by the xanthomonas citri subsp. citri type iii secretion system, and the cytosolic domain of the inner membrane protein hrcu, a paralog of the flagellar protein flhb. we show that a recombinant fragment corresponding to the c-terminal cytosolic domain of hrcu produced in e. coli suffers cleavage within a conserved asn264-pro265-thr266- ...201121408079
protection of arabidopsis thaliana against leaf-pathogenic pseudomonas syringae by sphingomonas strains in a controlled model system.diverse bacterial taxa live in association with plants without causing deleterious effects. previous analyses of phyllosphere communities revealed the predominance of few bacterial genera on healthy dicotyl plants, provoking the question of whether these commensals play a particular role in plant protection. here, we tested two of them, methylobacterium and sphingomonas, with respect to their ability to diminish disease symptom formation and the proliferation of the foliar plant pathogen pseudom ...201121421777
oxa-163, an oxa-48-related class d ß-lactamase with extended activity toward expanded-spectrum cephalosporins.two bla(oxa-48)-like-positive isolates (klebsiella pneumoniae and enterobacter cloacae) were recovered in argentina in 2008 as part of a large-scale survey focused on multidrug resistance in enterobacteriaceae. in both cases, sequencing identified ß-lactamase oxa-163, differing from oxa-48 by a single amino substitution and a 4-amino-acid deletion. oxa-163 hydrolyzed penicillins, ceftazidime, and cefotaxime, whereas oxa-48 did not. however, oxa-163 had a much lower ability to hydrolyze carbapene ...201121422200
defense response of a pepper cultivar cv. sy-2 is induced at temperatures below 24°c.temperature is one of the most important environmental factors that influence plant growth and development. recent studies imply that plants show various responses to non-extreme ambient temperatures. previously, we have found that a pepper cultivar cv. sy-2 (capsicum chinense) shows developmental defects at temperatures below 24°c. in this study, to gain new insights into the temperature sensitivity of cv. sy-2, temperature-sensitive genes were screened using microarray techniques. at restricti ...201121424609
phylogenetic distribution and evolutionary history of bacterial dead-box proteins.dead-box proteins are found in all domains of life and participate in almost all cellular processes that involve rna. the presence of dead and helicase_c conserved domains distinguish these proteins. dead-box proteins exhibit rna-dependent atpase activity in vitro, and several also show rna helicase activity. in this study, we analyzed the distribution and architecture of dead-box proteins among bacterial genomes to gain insight into the evolutionary pathways that have shaped their history. we i ...201121437710
indigenous populations of three closely related lysobacter spp. in agricultural soils using real-time pcr.previous research had shown that three closely related species of lysobacter, i.e., lysobacter antibioticus, lysobacter capsici, and lysobacter gummosus, were present in different rhizoctonia-suppressive soils. however, the population dynamics of these three lysobacter spp. in different habitats remains unknown. therefore, a specific primer-probe combination was designed for the combined quantification of these three lysobacter spp. using taqman. strains of the three target species were efficien ...201121448673
solution structure of lci, a novel antimicrobial peptide from bacillus subtilis.lci, a 47-residue cationic antimicrobial peptide (amp) found in bacillus subtilis, is one of the main effective components that have strong antimicrobial activity against xanthomonas campestris pv oryzea and pseudomonas solanacearum pe1, etc. to provide insight into the activity of the peptide, we used nuclear magnetic resonance spectroscopy to determine the structure of recombinant lci. the solution structure of lci has a novel topology, containing a four-strand antiparallel ß-sheet as the domi ...201121449609
cloning and characterization of a 9-lipoxygenase gene induced by pathogen attack from nicotiana benthamiana for biotechnological application.plant lipoxygenases (loxs) have been proposed to form biologically active compounds both during normal developmental stages such as germination or growth as well as during responses to environmental stress such as wounding or pathogen attack. in our previous study, we found that enzyme activity of endogenous 9-lox in nicotiana benthamiana was highly induced by agroinfiltration using a tobacco mosaic virus (tmv) based vector system.201121450085
antibacterial activity of metabolite produced by paenibacillus polymyxa strain hka-15 against xanthomonas campestris pv. phaseoli.an antibacterial metabolite extracted from paenibacillus polymyxa hka-15 showed strong inhibition against xanthomonas campestris pv. phaseoli strains cp-1-1 and m-5. minimum inhibitory concentration (mic) of crude extract against strains cp-1-1 and m-5 was found to be 1.7 mg/ml and 1.52 mg/ml, respectively. in uv-vis range, the absorption peak of crude extract was maximum at 240 nm. the compound is resilience to wide range of temperature, ph, surfactants and organic solvents. the complete loss o ...201121452603
distributed structure determination at the jcsg.the joint center for structural genomics (jcsg), one of four large-scale structure-determination centers funded by the us protein structure initiative (psi) through the national institute for general medical sciences, has been operating an automated distributed structure-solution pipeline, xsolve, for well over half a decade. during psi-2, xsolve solved, traced and partially refined 90% of the jcsg's nearly 770 mad/sad structures at an average resolution of about 2 å without human intervention. ...201121460455
hpa2 required by hrpf to translocate xanthomonas oryzae transcriptional activator-like effectors into rice for pathogenicity.xanthomonas oryzae pv. oryzicola, the causative agent of bacterial leaf streak, injects a plethora of effectors through the type iii secretion system (t3ss) into rice cells to cause disease. the t3ss, encoded by the hrp genes, is essential for the pathogen to elicit the hypersensitive response (hr) in nonhost tobacco and for pathogenicity in host rice. whether or not a putative lytic transglycosylase, hpa2, interacts with a translocon protein, hrpf, to facilitate bacterial pathogenicity remains ...201121478322
l-fucose utilization provides campylobacter jejuni with a competitive advantage.campylobacter jejuni is a prevalent gastrointestinal pathogen in humans and a common commensal of poultry. when colonizing its hosts, c. jejuni comes into contact with intestinal carbohydrates, including l-fucose, released from mucin glycoproteins. several strains of c. jejuni possess a genomic island (cj0480c-cj0490) that is up-regulated in the presence of both l-fucose and mucin and allows for the utilization of l-fucose as a substrate for growth. strains possessing this genomic island show in ...201121482772
xerr, a negative regulator of xccr in xanthomonas campestris pv. campestris, relieves its repressor function in planta.we previously reported that xccr, a luxr-type regulator of xanthomonas campestris pv. campestris (xcc), activates the downstream proline iminopeptidase virulence gene (pip) in response to certain host plant factor(s). in this report, we further show that the expression of the xccr gene was repressed in the culture medium by an ntrc-type response regulator, which we named xerr (xccr expression-related, repressor), and that this repression was relieved when the bacteria were grown in planta. such ...201121483448
c-di-gmp turn-over in clostridium difficile is controlled by a plethora of diguanylate cyclases and phosphodiesterases.clostridium difficile infections have become a major healthcare concern in the last decade during which the emergence of new strains has underscored this bacterium's capacity to cause persistent epidemics. c-di-gmp is a bacterial second messenger regulating diverse bacterial phenotypes, notably motility and biofilm formation, in proteobacteria such as vibrio cholerae, pseudomonas aeruginosa, and salmonella. c-di-gmp is synthesized by diguanylate cyclases (dgcs) that contain a conserved ggdef dom ...201121483756
quantifying of bactericide properties of medicinal plants.extended research has been carried out to clarify the ecological role of plant secondary metabolites (sms). although their primary ecological function is self-defence, bioactive compounds have long been used in alternative medicine or in biological control of pests. several members of the family labiatae are known to have strong antimicrobial capacity. for testing and quantifying antibacterial activity, most often standard microbial protocols are used, assessing inhibitory activity on a selected ...201121502819
molecular characterization of copper resistance genes from xanthomonas citri subsp. citri and xanthomonas alfalfae subsp. citrumelonis.copper sprays have been widely used for control of endemic citrus canker caused by xanthomonas citri subsp. citri (xcc) in citrus-growing areas for more than two decades. xanthomonas alfalfae subsp. citrumelonis (xac) populations were also exposed to frequent sprays of copper for several years as a protective measure against citrus bacterial spot (cbs) in florida citrus nurseries. long term use of these bactericides has led to the development of copper resistant (cu(r)) strains in both xcc and x ...201121515725
genomic analysis of xanthomonas oryzae from us rice reveals substantial divergence from known x. oryzae pathovars.the species xanthomonas oryzae is comprised of two designated pathovars, both of which cause economically significant diseases of rice in asia and africa. although x. oryzae is not considered endemic to the united states, an x. oryzae-like bacterium was isolated from us rice and southern cutgrass in the late 1980s. the us strains were weakly pathogenic and genetically distinct from characterized x. oryzae pathovars. in the current study, draft genome sequence from two us xanthomonas strains reve ...201121515727
identification and characterization of cdgb, a diguanylate cyclase involved in developmental processes in streptomyces coelicolor.we describe the identification and functional characterization of cdgb (sco4281), a recently discovered target of bldd, a key regulator of morphological differentiation and antibiotic production in the mycelial bacteria of the genus streptomyces. cdgb (cyclic dimeric gmp [c-di-gmp] b) encodes a ggdef-containing protein that has diguanylate cyclase activity in vitro. consistent with this enzymatic activity, heterologous expression of cdgb in escherichia coli resulted in increased production of ex ...201121515767
bioinformatic characterization of the trimeric intracellular cation-specific channel protein family.trimeric intracellular cation-specific (tric) channels are integral to muscle excitation-contraction coupling. tric channels provide counter-ionic flux when calcium is rapidly transported from intracellular stores to the cell cytoplasm. until recently, knowledge of the presence of these proteins was limited to animals. we analyzed the tric family and identified a profusion of prokaryotic family members with topologies and motifs similar to those of their eukaryotic counterparts. prokaryotic memb ...201121519847
the complete genome sequence of fibrobacter succinogenes s85 reveals a cellulolytic and metabolic specialist.fibrobacter succinogenes is an important member of the rumen microbial community that converts plant biomass into nutrients usable by its host. this bacterium, which is also one of only two cultivated species in its phylum, is an efficient and prolific degrader of cellulose. specifically, it has a particularly high activity against crystalline cellulose that requires close physical contact with this substrate. however, unlike other known cellulolytic microbes, it does not degrade cellulose using ...201121526192
prevalence of sos-mediated control of integron integrase expression as an adaptive trait of chromosomal and mobile integrons.abstract:201121529368
a bacterial sub-family of luxr regulators that respond to plant compounds.pseudomonas fluorescens are rhizobacteria known for their biocontrol properties; several antimicrobial functions are crucial for this process; experiments here investigate the modulation of their expression during the plant-bacterial interaction. the role of a luxr family regulator in interkingdom signalling has been investigated using genome-scale transcriptome analysis, gene promoter studies in vivo and in vitro, biocontrol assays and response to plant compounds. psor, a luxr solo or orphan re ...201121531826
classification of plant associated bacteria using rif, a computationally derived dna marker.a dna marker that distinguishes plant associated bacteria at the species level and below was derived by comparing six sequenced genomes of xanthomonas, a genus that contains many important phytopathogens. this dna marker comprises a portion of the dnaa replication initiation factor (rif). unlike the rrna genes, dnaa is a single copy gene in the vast majority of sequenced bacterial genomes, and amplification of rif requires genus-specific primers. in silico analysis revealed that rif has equal or ...201121533033
evidence for reductive genome evolution and lateral acquisition of virulence functions in two corynebacterium pseudotuberculosis strains.corynebacterium pseudotuberculosis, a gram-positive, facultative intracellular pathogen, is the etiologic agent of the disease known as caseous lymphadenitis (cl). cl mainly affects small ruminants, such as goats and sheep; it also causes infections in humans, though rarely. this species is distributed worldwide, but it has the most serious economic impact in oceania, africa and south america. although c. pseudotuberculosis causes major health and productivity problems for livestock, little is k ...201121533164
pepper asparagine synthetase 1 (caas1) is required for plant nitrogen assimilation and defense responses to microbial pathogens.asparagine synthetase is a key enzyme in the production of the nitrogen-rich amino acid asparagine, which is crucial to primary nitrogen metabolism. despite its importance physiologically, the roles that asparagine synthetase plays during plant defense responses remain unknown. here, we determined that pepper (capsicum annuum) asparagine synthetase 1 (caas1) is essential for plant defense to microbial pathogens. infection with xanthomonas campestris pv. vesicatoria (xcv) induced early and strong ...201121535260
xanthomonas campestris diffusible factor is 3-hydroxybenzoic acid and associated with xanthomonadin biosynthesis, cell viability, antioxidant activity and systemic invasion.xanthomonas campestris pv. campestris (xcc) produces a membrane-bound yellow pigment xanthomonadin. a diffusible factor (df) has been reported to regulate xanthomonadin biosynthesis. in this study df was purified from bacterial culture supernatants using a combination of solvent extraction, flash chromatography and high performance liquid chromatography (hplc). mass spectrometry (ms) and nuclear magnetic resonance (nmr) analyses resolved the df chemical structure as 3-hydroxybenzoic acid (3-hba) ...201121539432
isolation of xylose isomerases by sequence- and function-based screening from a soil metagenome library.abstract: background: xylose isomerase (xi) catalyses the isomerization of xylose to xylulose in bacteria and some fungi. currently, only a limited number of xi genes have been functionally expressed in saccharomyces cerevisiae, the microorganism of choice for lignocellulosic ethanol production. the objective of the present study was to search for novel xi genes in the vastly diverse microbial habitat present in soil. as the exploitation of microbial diversity is impaired by the ability to culti ...201121545702
crystal structures of slya, a master virulence regulator of salmonella, in free and dna-bound states.slya is a master virulence regulator that controls the transcription of numerous genes in salmonella enterica. we present here crystal structures of slya by itself and bound to a high-affinity dna operator sequence in the slya gene. slya interacts with dna through direct recognition of a guanine base by r65, as well as interactions between conserved r86 and the minor groove and a large network of non-base-specific contacts to the sugar-phosphate backbone. our structures, together with an unpubli ...201121550983
hybrid modeling of xanthan gum bioproduction in batch bioreactor.this work is focused on hybrid modeling of xanthan gum bioproduction process by xanthomonas campestris pv. mangiferaeindicae. experiments were carried out to evaluate the effects of stirred speed and superficial gas velocity on the kinetics of cell growth, lactose consumption and xanthan gum production in a batch bioreactor using cheese whey as substrate. a hybrid model was employed to simulate the bio-process making use of an artificial neural network (ann) as a kinetic parameter estimator for ...201121553014
yqic of salmonella enterica serovar typhimurium is a membrane fusogenic protein required for mice colonization.abstract:201121554724
resistance to organic hydroperoxides requires ohr and ohrr genes in sinorhizobium meliloti.abstract:201121569462
ghmpk16, a novel stress-responsive group d mapk gene from cotton, is involved in disease resistance and drought sensitivity.abstract: background: mitogen-activated protein kinase (mapk) cascades play pivotal roles in mediating biotic and abiotic stress responses. in plants, mapks are classified into four major groups (a-d) according to their sequence homology and conserved phosphorylation motifs. members of group a and b have been extensively explored, but little information on the group d mapks has been reported. results: in this study, we isolated and characterized ghmpk16, the first group d mapk gene found in cott ...201121575189
functional characterization of the type iii secretion substrate specificity switch protein hpac from xanthomonas.pathogenicity of xanthomonas campestris pv. vesicatoria depends on a type iii secretion (t3s) system which translocates effector proteins into eukaryotic cells and is associated with an extracellular pilus and a translocon in the host plasma membrane. t3s substrate specificity is controlled by the cytoplasmic switch protein hpac which interacts with the c-terminal domain of the inner membrane protein hrcu (hrcu(c)). hpac promotes the secretion of translocon and effector proteins but prevents the ...201121576326
the arabidopsis flagellin receptor fls2 mediates the perception of xanthomonas ax21 secreted peptides.detection of microbes by plants relies in part on an array of pattern-recognition receptors that recognize conserved microbial signatures, so-called "microbe-associated molecular patterns." the arabidopsis thaliana receptor-like kinase fls2 is the pattern-recognition receptor for bacterial flagellin. similarly to fls2, the rice transmembrane protein xa21 is the receptor for the sulfated form of the xanthomonas oryzae pv. oryzae secreted protein ax21. here we show that ax21-derived peptides activ ...201121576467
a component of the xanthomonadaceae type iv secretion system combines a virb7 motif with a n0 domain found in outer membrane transport proteins.type iv secretion systems (t4ss) are used by gram-negative bacteria to translocate protein and dna substrates across the cell envelope and into target cells. translocation across the outer membrane is achieved via a ringed tetradecameric outer membrane complex made up of a small virb7 lipoprotein (normally 30 to 45 residues in the mature form) and the c-terminal domains of the virb9 and virb10 subunits. several species from the genera of xanthomonas phytopathogens possess an uncharacterized type ...201121589901
structural analysis and involvement in plant innate immunity of xanthomonas axonopodis pv. citri lipopolysaccharide.xanthomonas axonopodis pv. citri causes citrus canker, provoking defoliation and premature fruit drop with the concomitant economical damage. in plant pathogenic bacteria, lipopolysaccharides are important virulence factors and they are being increasingly recognized as major pathogen associated molecular patterns for plants. in general three domains are recognized in a lipopolysaccharide: the hydrophobic lipid a, the hydrophilic o-antigen polysaccharide and the core oligosaccharide, connecting l ...201121596742
structure of the pilm-piln inner membrane type iv pilus biogenesis complex from thermus thermophilus.type iv pili are surface-exposed filaments which extend from a variety of bacterial pathogens and play a major role in pathogenesis, motility and dna uptake. here we present the crystal structure of a complex between a cytoplasmic component of the type iv pilus biogenesis system from thermus thermophilus, pilm, in complex with a peptide derived from the cytoplasmic portion of the inner membrane protein piln. pilm also binds atp, and its structure is most similar to the actin-like protein ftsa. p ...201121596754
exploring the metabolic network of the epidemic pathogen burkholderia cenocepacia j2315 via genome-scale reconstruction.abstract: background: burkholderia cenocepacia is a threatening nosocomial epidemic pathogen in patients with cystic fibrosis (cf) or a compromised immune system. its high level of antibiotic resistance is an increasing concern in treatments against its infection. strain b. cenocepacia j2315 is the most infectious isolate from cf patients. there is a strong demand to reconstruct a genome-scale metabolic network of b. cenocepacia j2315 to systematically analyze its metabolic capabilities and its ...201121609491
dual transcriptional profiling of a bacterial/fungal confrontation: collimonas fungivorans versus aspergillus niger.interactions between bacteria and fungi cover a wide range of incentives, mechanisms and outcomes. the genus collimonas consists of soil bacteria that are known for their antifungal activity and ability to grow at the expense of living fungi. in non-contact confrontation assays with the fungus aspergillus niger, collimonas fungivorans showed accumulation of biomass concomitant with inhibition of hyphal spread. through microarray analysis of bacterial and fungal mrna from the confrontation arena, ...201121614084
systematic mutagenesis of all predicted gntr genes in xanthomonas campestris pv. campestris reveals a gntr family transcriptional regulator controlling hypersensitive response and virulence.the gntr family is one of the most abundant and widely distributed groups of helix-turn-helix transcriptional regulators in bacteria. six open reading frames in the genome of the plant pathogen xanthomonas campestris pv. campestris were predicted to encode putative gntr regulators. in this work, all of the all six of the predicted gntr-encoding genes were individually exposed to mutagenesis mutagenized and mutants derived from five of them were successfully obtained. plant disease response assay ...201121615202
streptomyces gramineus sp. nov., an antibacterial-producing actinobacterium isolated from bamboo (sasa boreali) rhizosphere soil.two actinobacterial strains, jr-43(t) and jr-4, were isolated from bamboo (sasa boreali) rhizosphere soil. the isolates produced grey aerial mycelium and a yellow soluble pigment on isp 4. microscopic observation revealed that strains jr-43(t) and jr-4 produced rectiflexibiles spore chains with spiny surfaces. both strains had antibacterial activity against plant pathogenic bacteria, such as xanthomonas campestris lmg 568(t) and xanthomonas axonopodis pv. vesicatoria lmg 905(t). the strains cont ...201121622836
the pepper e3 ubiquitin ligase ring1 gene, caring1, is required for cell death and the salicylic acid-dependent defense response.ubiquitination is essential for ubiquitin/proteasome-mediated protein degradation in plant development and defense. here, we identified a novel e3 ubiquitin ligase ring1 gene, caring1, from pepper (capsicum annuum). in pepper, caring1 expression is induced by avirulent xanthomonas campestris pv. vesicatoria (xcv) infection. caring1 contains an n-terminal transmembrane domain and a c-terminal ring domain. in addition, it displays in vitro e3 ubiquitin ligase activity and the ring domain is essent ...201121628629
enzyme reactivation by hydrogen peroxide in heme-based tryptophan dioxygenase.an intriguing mystery about tryptophan 2,3-dioxygenase (tdo) is its hydrogen peroxide-triggered enzyme reactivation from the resting ferric oxidation state to the catalytically active ferrous form. in this work, we find that such an odd fe(iii) reduction by an oxidant depends on the presence of l-trp, which ultimately serves as the reductant for the enzyme. in the peroxide reaction with tdo, a previously unknown catalase-like activity is detected. a ferryl species (δ = 0.055 mm/s and δe(q) = 1.7 ...201121632548
substrate and product analogues as human o-glcnac transferase inhibitors.protein glycosylation on serine/threonine residues with n-acetylglucosamine (o-glcnac) is a dynamic, inducible and abundant post-translational modification. it is thought to regulate many cellular processes and there are examples of interplay between o-glcnac and protein phosphorylation. in metazoa, a single, highly conserved and essential gene encodes the o-glcnac transferase (ogt) that transfers glcnac onto substrate proteins using udp-glcnac as the sugar donor. specific inhibitors of human og ...201120640461
substrate and product analogues as human o-glcnac transferase inhibitors.protein glycosylation on serine/threonine residues with n-acetylglucosamine (o-glcnac) is a dynamic, inducible and abundant post-translational modification. it is thought to regulate many cellular processes and there are examples of interplay between o-glcnac and protein phosphorylation. in metazoa, a single, highly conserved and essential gene encodes the o-glcnac transferase (ogt) that transfers glcnac onto substrate proteins using udp-glcnac as the sugar donor. specific inhibitors of human og ...201120640461
the xanthomonas campestris pv. vesicatoria cith gene is expressed early in the infection process of tomato and is positively regulated by the tctde two-component regulatory system.xanthomonas campestris pv. vesicatoria (xcv) is the causal agent of bacterial spot disease of tomato and pepper. previously, we have reported the adaptation of a recombinase- or resolvase-based in vivo expression technology (rivet) approach to identify xcv genes that are specifically induced during its interaction with tomato. analysis of some of these genes revealed that a cith (citrate transporter) homologous gene contributes to xcv virulence on tomato. here, we demonstrate that the cith produ ...201121118349
the pepper mannose-binding lectin gene cambl1 is required to regulate cell death and defense responses to microbial pathogens.plant mannose-binding lectins (mbls) are crucial for plant defense signaling during pathogen attack by recognizing specific carbohydrates on pathogen surfaces. in this study, we isolated and functionally characterized a novel pepper (capsicum annuum) mbl gene, cambl1, from pepper leaves infected with xanthomonas campestris pv vesicatoria (xcv). the cambl1 gene contains a predicted galanthus nivalis agglutinin-related lectin domain responsible for the recognition of high-mannose n-glycans but lac ...201121205632
oligomerization of epse coordinates residues from multiple subunits to facilitate atpase activity.epse is an atpase that powers transport of cholera toxin and hydrolytic enzymes through the type ii secretion (t2s) apparatus in the gram-negative bacterium, vibrio cholerae. on the basis of structures of homologous type ii/iv secretion atpases and our biochemical data, we believe that epse is active as an oligomer, likely a hexamer, and the binding, hydrolysis, and release of nucleotide cause epse to undergo dynamic structural changes, thus converting chemical energy to mechanical work, ultimat ...201121209100
nanopods: a new bacterial structure and mechanism for deployment of outer membrane vesicles.bacterial outer membrane vesicles (omv) are packets of periplasmic material that, via the proteins and other molecules they contain, project metabolic function into the environment. while omv production is widespread in proteobacteria, they have been extensively studied only in pathogens, which inhabit fully hydrated environments. however, many (arguably most) bacterial habitats, such as soil, are only partially hydrated. in the latter, water is characteristically distributed as films on soil pa ...201121687732
complete genome sequence of the plant pathogen ralstonia solanacearum strain po82.ralstonia solanacearum strain po82, a phylotype iib/sequevar 4 strain, was found to be pathogenic to both solanaceous plants and banana. here, we report the complete genome sequence of po82 and its comparison with seven published r. solanacearum genomes.201121685279
lytic myophage abp53 encodes several proteins similar to those encoded by host acinetobacter baumannii and phage phiko2.acinetobacter baumannii is an important gram-negative opportunistic pathogen causing nosocomial infections. the emergence of multiple drug resistant a. baumannii isolates has increased in recent years. directed towards phage therapy, a lytic phage of a. baumannii, designated abp53, was isolated from a sputum sample in this study. abp53 has an isometric head and a contractile tail with tail fibers, belonging to myoviridae, a latent period of about 10 min, and a burst size of approximately 150 pfu ...201121821767
resolving the phylogenetic and taxonomic relationship of xanthomonas and stenotrophomonas strains using complete rpob gene sequence. 201121686310
comparative analysis of the xopd type iii secretion (t3s) effector family in plant pathogenic bacteria.xopd is a type iii effector protein that is required for xanthomonas campestris pathovar vesicatoria (xcv) growth in tomato. it is a modular protein consisting of an n-terminal dna-binding domain, two ethylene-responsive element binding factor-associated amphiphilic repression (ear) transcriptional repressor motifs and a c-terminal small ubiquitin-related modifier (sumo) protease. in tomato, xopd functions as a transcriptional repressor, resulting in the suppression of defence responses at late ...201121726373
microarray based analysis of inca/c plasmid associated genes from multidrug resistant salmonella enterica.in enterobacteriaceae, plasmids have been classified according to 27 incompatibility (inc) or replicon types which are based on the inability of different plasmids with the same replication mechanism to co-exist in the same cell. certain replicon types such as inca/c are associated with multidrug resistance (mdr). we developed a microarray that contains 286 unique 70 mer oligonucleotide probes based on sequences from five inca/c plasmids: pyr1 (yersinia ruckeri), ppip1202 (yersinia pestis), pp99 ...201121841024
synergistic use of plant-prokaryote comparative genomics for functional annotations.identifying functions for all gene products in all sequenced organisms is a central challenge of the post-genomic era. however, at least 30-50% of the proteins encoded by any given genome are of unknown or vaguely known function, and a large number are wrongly annotated. many of these 'unknown' proteins are common to prokaryotes and plants. we set out to predict and experimentally test the functions of such proteins. our approach to functional prediction integrates comparative genomics based mai ...201121810204
Biochemical and Mutational Studies of the Bacillus cereus CECT 5050T Formamidase Support the Existence of a C-E-E-K Tetrad in Several Members of the Nitrilase Superfamily.Formamidases (EC 3.5.1.49) are poorly characterized proteins. In spite of this scarce knowledge, ammonia has been described as playing a central role in the pathogenesis of human pathogens such as Helicobacter pylori, for which formamidase has been shown to participate in the nitrogen metabolic pathway. Sequence analysis has revealed that at least two different groups of formamidases are classified as EC 3.5.1.49: on the one hand, the derivatives of the FmdA-AmdA superfamily, which are the best ...201121705545
application of image analysis in studies of quantitative disease resistance: exemplified using common bacterial blight-common bean pathosystem.the effectiveness of image analysis (ia), compared with an ordinal visual scale, for quantitative measurement of disease severity, its application in quantitative genetic studies, and its effect on the estimates of genetic parameters were investigated. studies were performed using eight backcross-derived families of common bean (phaseolus vulgaris l.) (n=172) segregating for the molecular marker su91, known to be associated with a quantitative trait loci (qtl) for resistance to common bacterial ...201122204655
pyrroloquinoline quinone biosynthesis gene pqqc, a novel molecular marker for studying the phylogeny and diversity of phosphate-solubilizing pseudomonads.many root-colonizing pseudomonads are able to promote plant growth by increasing phosphate availability in soil through solubilization of poorly soluble rock phosphates. the major mechanism of phosphate solubilization by pseudomonads is the secretion of gluconic acid, which requires the enzyme glucose dehydrogenase and its cofactor pyrroloquinoline quinone (pqq). the main aim of this study was to evaluate whether a pqq biosynthetic gene is suitable to study the phylogeny of phosphate-solubilizin ...201121856827
Structural insights into the glycosyltransferase activity of the Actinobacillus pleuropneumoniae HMW1C-like protein.Glycosylation of proteins is a fundamental process that influences protein function. The Haemophilus influenzae HMW1 adhesin is an N-linked glycoprotein that mediates adherence to respiratory epithelium, an essential early step in the pathogenesis of H. influenzae disease. HMW1 is glycosylated by HMW1C, a novel glycosyltransferase in the GT41 family that creates N-glycosidic linkages with glucose and galactose at asparagine residues and di-glucose linkages at sites of glucose modification. Here ...201121908603
Phage-based biocontrol strategies to reduce foodborne pathogens in foods.There has been much recent interest in the use of phages as biocontrol agents of foodborne pathogens in animals used for food production, and in the food products themselves. This interest seems to be driven by consumers' request for more natural foods, as well as the fact that foodborne outbreaks continue to occur, globally, in many foods, some of which (such as fresh produce), lack adequate methods to control any pathogenic contamination present. Also, the many successes with respect to regula ...201122164346
crosstalk between ros homeostasis and secondary metabolism in s. natalensis atcc 27448: modulation of pimaricin production by intracellular ros.streptomyces secondary metabolism is strongly affected by oxygen availability. the increased culture aeration enhances pimaricin production in s. natalensis, however the excess of o(2) consumption can lead to an intracellular ros imbalance that is harmful to the cell. the adaptive physiological response of s. natalensis upon the addition of exogenous h(2)o(2) suggested that the modulation of the intracellular ros levels, through the activation of the h(2)o(2) inducible catalase during the late e ...201122114674
role of escu auto-cleavage in promoting type iii effector translocation into host cells by enteropathogenic escherichia coli.type iii secretion systems (t3ss) of bacterial pathogens coordinate effector protein injection into eukaryotic cells. the yscu/flhb group of proteins comprises members associated with t3ss which undergo a specific auto-cleavage event at a conserved npth amino acid sequence. the crystal structure of the c-terminal portion of escu from enteropathogenic escherichia coli (epec) suggests this auto-cleaving protein provides an interface for substrate interactions involved in type iii secretion events.201121933418
Genomes and Virulence Factors of Novel Bacterial Pathogens Causing Bleaching Disease in the Marine Red Alga Delisea pulchra.Nautella sp. R11, a member of the marine Roseobacter clade, causes a bleaching disease in the temperate-marine red macroalga, Delisea pulchra. To begin to elucidate the molecular mechanisms underpinning the ability of Nautella sp. R11 to colonize, invade and induce bleaching of D. pulchra, we sequenced and analyzed its genome. The genome encodes several factors such as adhesion mechanisms, systems for the transport of algal metabolites, enzymes that confer resistance to oxidative stress, cytolys ...201122162749
effect of glutaraldehyde fixation on bacterial cells observed by atomic force microscopy.atomic force microscopy (afm) is a promising microscopy technique that can provide high-resolution images of bacterial cells without fixation. three species of bacteria, xanthomonas campestris, pseudomonas syringae, and bacillus subtilis, were used in this study. afm images were obtained from unfixed and glutaraldehyde-fixed cells, and cell height was measured. the mean height of bacterial cells prepared by fixation was higher than that of those prepared by nonfixation. however, the height chang ...201121898456
the structure of an unconventional hd-gyp protein from bdellovibrio reveals the roles of conserved residues in this class of cyclic-di-gmp phosphodiesterases.cyclic-di-gmp is a near-ubiquitous bacterial second messenger that is important in localized signal transmission during the control of various processes, including virulence and switching between planktonic and biofilm-based lifestyles. cyclic-di-gmp is synthesized by ggdef diguanylate cyclases and hydrolyzed by eal or hd-gyp phosphodiesterases, with each functional domain often appended to distinct sensory modules. hd-gyp domain proteins have resisted structural analysis, but here we present th ...201121990613
Genome-wide transcriptome analysis of the plant pathogen Xanthomonas identifies sRNAs with putative virulence functions.The Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) is an important model to elucidate the mechanisms involved in the interaction with the host. To gain insight into the transcriptome of the Xcv strain 85-10, we took a differential RNA sequencing (dRNA-seq) approach. Using a novel method to automatically generate comprehensive transcription start site (TSS) maps we report 1421 putative TSSs in the Xcv genome. Genes in Xcv exhibit a poorly conserved -10 promo ...201122080557
Genome-wide transcriptome analysis of the plant pathogen Xanthomonas identifies sRNAs with putative virulence functions.The Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) is an important model to elucidate the mechanisms involved in the interaction with the host. To gain insight into the transcriptome of the Xcv strain 85-10, we took a differential RNA sequencing (dRNA-seq) approach. Using a novel method to automatically generate comprehensive transcription start site (TSS) maps we report 1421 putative TSSs in the Xcv genome. Genes in Xcv exhibit a poorly conserved -10 promo ...201122080557
Kinetic and thermodynamic features reveal that Escherichia coli BCP is an unusually versatile peroxiredoxin.In Escherichia coli, bacterioferritin comigratory protein (BCP) is a peroxiredoxin (Prx) that catalyzes the reduction of H(2)O(2) and organic hydroperoxides. This protein, along with plant PrxQ, is a founding member of one of the least studied subfamilies of Prxs. Recent structural data have suggested that proteins in the BCP/PrxQ group can exist as monomers or dimers; we report here that, by analytical ultracentrifugation, both oxidized and reduced E. coli BCP behave as monomers in solution at ...201121910476
palmaenones a and b, two new antimicrobial chlorinated cyclopentenones from discomycete lachnum palmae.two new antimicrobial chlorinated cyclopentenones, palmaenones a (1) and b (2) were isolated from the culture broth of discomycete lachnum palmae (nbrc-106495), and the structures of 1 and 2 were elucidated by spectroscopic data and the stereochemistry of 1 was directly determined by a single-crystal x-ray diffraction analysis. palmaenones a (1) and b (2) are cyclopentenones containing three chlorines. compound 1 exhibited potent antimicrobial activity against micrococcus luteus, mycobacterium s ...201122130381
A secreted lipolytic enzyme from Xanthomonas campestris pv. vesicatoria is expressed in planta and contributes to its virulence.A recombinase-based in vivo expression technology (RIVET) approach with Xanthomonas campestris pv. vesicatoria (Xcv) revealed that lipA, annotated as putative secreted lipase, is expressed during the interaction between this pathogen and tomato. Here, the tnpR and uidA reporter genes were used to show that lipA is strongly induced in XVM2 minimal medium and during the early stages of tomato infection by Xcv. A mutant strain impaired in lipA was generated by insertional mutagenesis. This mutant g ...201122176521
arabidopsis seedling flood-inoculation technique: a rapid and reliable assay for studying plant-bacterial interactions.abstract:201121978451
arabidopsis lysin-motif proteins lym1 lym3 cerk1 mediate bacterial peptidoglycan sensing and immunity to bacterial infection.recognition of microbial patterns by host pattern recognition receptors is a key step in immune activation in multicellular eukaryotes. peptidoglycans (pgns) are major components of bacterial cell walls that possess immunity-stimulating activities in metazoans and plants. here we show that pgn sensing and immunity to bacterial infection in arabidopsis thaliana requires three lysin-motif (lysm) domain proteins. lym1 and lym3 are plasma membrane proteins that physically interact with pgns and medi ...201122106285
ralstonia syzygii, the blood disease bacterium and some asian r. solanacearum strains form a single genomic species despite divergent lifestyles.the ralstonia solanacearum species complex includes r. solanacearum, r. syzygii, and the blood disease bacterium (bdb). all colonize plant xylem vessels and cause wilt diseases, but with significant biological differences. r. solanacearum is a soilborne bacterium that infects the roots of a broad range of plants. r. syzygii causes sumatra disease of clove trees and is actively transmitted by cercopoid insects. bdb is also pathogenic to a single host, banana, and is transmitted by pollinating ins ...201121931687
mutational biosynthesis of neomycin analogs by a mutant of neomycin-producing streptomyces fradiae.neomycin, produced by streptomyces fradiae, has been widely used for the treatment of bacterial infections in clinical and agricultural applications. in this study, a neomycin nonproducing mutant of s. fradiae was obtained by gene disruption technique for mutational biosynthesis. a crucial gene neoc (neo7) which encodes 2-deoxystreptamine (2-dos) synthases was disrupted. the mutant could resume producing neomycin in the presence of 2-dos. salen derivatives of 2-dos were synthesized and individua ...201122083789
the pepper receptor-like cytoplasmic protein kinase capik1 is involved in plant signaling of defense and cell-death responses.certain protein kinases have been shown to be crucial for plant cell signaling pathways associated with plant immune responses. here we identified a pepper (capsicum annuum) receptor-like cytoplasmic protein kinase (rlck) gene (capik1) that is transcriptionally activated by infection with xanthomonas campestris pv. vesicatoria (xcv). silencing of capik1 in pepper plants confers enhanced susceptibility to xcv infection. salicylic acid-dependent defense responses are attenuated in the capik1-silen ...201121299658
overexpression, purification, crystallization and preliminary x-ray crystallographic analysis of the c-terminal domain of the gyra subunit of dna gyrase from staphylococcus aureus strain mu50.dna gyrase is a type ii topoisomerase that is essential for chromosome segregation and cell division owing to its ability to modify the topological form of bacterial dna. in this study, the c-terminal domain of the gyra subunit of dna gyrase from staphylococcus aureus mu50 strain was overexpressed in escherichia coli, purified and crystallized. diffraction data were collected to 2.80 å resolution using a synchrotron-radiation source. the crystal belonged to space group p2(1), with unit-cell para ...201121301105
new detection systems of bacteria using highly selective media designed by smart: selective medium-design algorithm restricted by two constraints.culturing is an indispensable technique in microbiological research, and culturing with selective media has played a crucial role in the detection of pathogenic microorganisms and the isolation of commercially useful microorganisms from environmental samples. although numerous selective media have been developed in empirical studies, unintended microorganisms often grow on such media probably due to the enormous numbers of microorganisms in the environment. here, we present a novel strategy for ...201121304596
structural basis for c-di-gmp-mediated inside-out signaling controlling periplasmic proteolysis.the bacterial second messenger bis-(3'-5') cyclic dimeric guanosine monophosphate (c-di-gmp) has emerged as a central regulator for biofilm formation. increased cellular c-di-gmp levels lead to stable cell attachment, which in pseudomonas fluorescens requires the transmembrane receptor lapd. lapd exhibits a conserved and widely used modular architecture containing a hamp domain and degenerate diguanylate cyclase and phosphodiesterase domains. c-di-gmp binding to the lapd degenerate phosphodieste ...201121304926
the involvement of jasmonates and ethylene in alternaria alternata f. sp. lycopersici toxin-induced tomato cell death.previous studies have shown that an ethylene (et)-dependent pathway is involved in the cell death signalling triggered by alternaria alternata f. sp. lycopersici (aal) toxin in detached tomato (solanum lycopersicum) leaves. in this study, the role of jasmonic acid (ja) signalling in programmed cell death (pcd) induced by aal toxin was analysed using a 35s::prosystemin transgenic line (35s::prosys), a ja-deficient mutant spr2, and a ja-insensitive mutant jai1. the results indicated that ja biosyn ...201121865178
bis-(3'-5')-cyclic dimeric gmp-linked quorum sensing controls swarming in vibrio parahaemolyticus.movement over and colonization of surfaces are important survival strategies for bacteria, and many find it advantageous to perform these activities as a group, using quorum sensing to sample population size and synchronize behavior. it is puzzling however, that swarming-proficient and virulent strains of vibrio parahaemolyticus are silenced for the vibrio archetypal pathway of quorum sensing. here we describe the s-signal, a pheromone that can be communicated between cells in coculture to regul ...201122006340
light signaling mediated by pas domain-containing proteins in xanthomonas campestris pv. campestris.per-arnt-sim (pas) domains are important signaling modules that possibly monitor changes in various stimuli such as light. for the majority of pas domains that have been identified by sequence similarity, the biological function of the signaling pathways has not yet been experimentally investigated. thirty-three pas proteins were discovered in xanthomonas campestris pv. campestris (xcc) by genome/proteome analysis. thirteen pas proteins were identified as contributing to light signaling and xcc ...201122029486
in vitro reconstruction of the chain termination reaction in biosynthesis of the escherichia coli o9a o-polysaccharide: the chain-length regulator, wbdd, catalyzes the addition of methyl phosphate to the non-reducing terminus of the growing glycan.the escherichia coli o9a o-polysaccharide (o-ps) represents a model system for glycan biosynthesis and export by the atp-binding cassette (abc) transporter-dependent pathway. the polymannose o9a o-ps is synthesized using an undecaprenol-diphosphate-linked acceptor by mannosyltransferases located at the cytoplasmic membrane. an abc-transporter subsequently exports the polymer to the periplasm where it is assembled onto lipopolysaccharide prior to translocation to the cell surface. the chain lengt ...201121990359
type iii secretion-dependent host defence elicitation and type iii secretion-independent growth within leaves by xanthomonas campestris pv. campestris.in many plant-bacterial interactions, loss of the type iii secretion system (t3ss) severely reduces bacterial growth, symptom causation and suppression of defences in host plants. in the present study of xanthomonas campestris pv. campestris (xcc), xcc strain b305 grew better than strain b186 in arabidopsis thaliana after hydathode inoculation, and b305 strains mutated to the loss of t3ss (+öhrcc and/or +öhrpe; also +öhrcc+öflgbc) grew similarly to wild-type b305 in arabidopsis leaves. unlike xc ...201121726374
genetic and functional diversity of pseudomonas aeruginosa lipopolysaccharide.lipopolysccharide (lps) is an integral component of the pseudomonas aeruginosa cell envelope, occupying the outer leaflet of the outer membrane in this gram-negative opportunistic pathogen. it is important for bacterium-host interactions and has been shown to be a major virulence factor for this organism. structurally, p. aeruginosa lps is composed of three domains, namely, lipid a, core oligosaccharide, and the distal o antigen (o-ag). most p. aeruginosa strains produce two distinct forms of o- ...201121687428
virulence determinants, drug resistance and mobile genetic elements of laribacter hongkongensis: a genome-wide analysis. 201121711902
phylogenetic identification of fungi isolated from the marine sponge tethya aurantium and identification of their secondary metabolites.fungi associated with the marine sponge tethya aurantium were isolated and identified by morphological criteria and phylogenetic analyses based on internal transcribed spacer (its) regions. they were evaluated with regard to their secondary metabolite profiles. among the 81 isolates which were characterized, members of 21 genera were identified. some genera like acremonium, aspergillus, fusarium, penicillium, phoma, and trichoderma are quite common, but we also isolated strains belonging to gene ...201121731550
evaluation of the virulence of xanthomonas campestris pv. campestris mutant strains lacking functional genes in the oxyr regulon.xanthomonas campestris pv. campestris causes black rot in cruciferous crops. hydrogen peroxide (h(2)o(2)) production and accumulation is an important initial response in plant defense against invading microbes. the role of genes involved in the bacterial h(2)o(2) protection system in pathogenicity was evaluated. mutants of kata (encoding a monofunctional catalase) and, to a lesser extent, katg (encoding a catalase-peroxidase) and oxyr (encoding a h(2)o(2) sensor and a transcription regulator), a ...201121710133
cyclic di-gmp is essential for the survival of the lyme disease spirochete in ticks.cyclic dimeric gmp (c-di-gmp) is a bacterial second messenger that modulates many biological processes. although its role in bacterial pathogenesis during mammalian infection has been documented, the role of c-di-gmp in a pathogen's life cycle within a vector host is less understood. the enzootic cycle of the lyme disease pathogen borrelia burgdorferi involves both a mammalian host and an ixodes tick vector. the b. burgdorferi genome encodes a single copy of the diguanylate cyclase gene (rrp1), ...201121738477
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