Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| characterization of plasmid por1 from ornithobacterium rhinotracheale and construction of a shuttle plasmid. | the bacterium ornithobacterium rhinotracheale has been recognized as an emerging pathogen in poultry since about 10 years ago. knowledge of this bacterium and its mechanisms of virulence is still very limited. here we report the development of a transformation system that enables genetic modification of o. rhinotracheale. the system is based on a cryptic plasmid, por1, that was derived from an o. rhinotracheale strain of serotype k. sequencing indicated that the plasmid consisted of 14,787 nucle ... | 2004 | 15466524 |
| transcriptional analysis of biofilm formation processes in the anaerobic, hyperthermophilic bacterium thermotoga maritima. | thermotoga maritima, a fermentative, anaerobic, hyperthermophilic bacterium, was found to attach to bioreactor glass walls, nylon mesh, and polycarbonate filters during chemostat cultivation on maltose-based media at 80 degrees c. a whole-genome cdna microarray was used to examine differential expression patterns between biofilm and planktonic populations. mixed-model statistical analysis revealed differential expression (twofold or more) of 114 open reading frames in sessile cells (6% of the ge ... | 2004 | 15466556 |
| variation suggestive of horizontal gene transfer at a lipopolysaccharide (lps) biosynthetic locus in xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen of rice. | in animal pathogenic bacteria, horizontal gene transfer events (hgt) have been frequently observed in genomic regions that encode functions involved in biosynthesis of the outer membrane located lipopolysaccharide (lps). as a result, different strains of the same pathogen can have substantially different lps biosynthetic gene clusters. since lps is highly antigenic, the variation at lps loci is attributed to be of advantage in evading the host immune system. although lps has been suggested as a ... | 2004 | 15473911 |
| a phylogenetic analysis of wadi el natrun soda lake cellulase enrichment cultures and identification of cellulase genes from these cultures. | samples of sediments and surrounding soda soils (ss) from the extremely saline and alkaline lakes of the wadi el natrun in the libyan desert, egypt, were obtained in october 2000. anaerobic enrichment cultures were grown from these samples, dna isolated, and the bacterial diversity assessed by 16s rrna gene clone analysis. clones derived from lake sediments (ls) most closely matched clostridium spp., natronoincola histidinovorans, halocella cellulolytica, bacillus spp., and the cytophaga-flexiba ... | 2004 | 15480866 |
| hpab from xanthomonas campestris pv. vesicatoria acts as an exit control protein in type iii-dependent protein secretion. | the hrp (hypersensitive response and pathogenicity) gene cluster of the plant pathogenic bacterium xanthomonas campestris pv. vesicatoria encodes a type iii secretion (tts) system, which injects bacterial effector proteins into the plant cell. here, we characterized hpab (hpa, hrp-associated), which encodes a pathogenicity factor with typical features of a tts chaperone. we show that hpab is important for the efficient secretion of at least five effector proteins but is dispensable for the secre ... | 2004 | 15491365 |
| innate immunity in arabidopsis thaliana: lipopolysaccharides activate nitric oxide synthase (nos) and induce defense genes. | lipopolysaccharides (lps) are cell-surface components of gram-negative bacteria and are microbe-/pathogen-associated molecular patterns in animal pathosystems. as for plants, the molecular mechanisms of signal transduction in response to lps are not known. here, we show that arabidopsis thaliana reacts to lps with a rapid burst of no, a hallmark of innate immunity in animals. fifteen lps preparations (among them burkholderia cepacia, pseudomonas aeruginosa, and erwinia carotovora) as well as lip ... | 2004 | 15498873 |
| diversity and antagonistic potential of bacteria associated with bryophytes from nutrient-poor habitats of the baltic sea coast. | very little is known about the interaction of bryophytes with bacteria. therefore, we analyzed bacteria associated with three bryophyte species, tortula ruralis, aulacomnium palustre, and sphagnum rubellum, which represent typical moss species of three nutrient-poor plant communities at the southern baltic sea coast in germany. by use of two cultivation-independent techniques, denaturing gradient gel electrophoresis and single-strand conformation polymorphism analysis of the 16s ribosomal dna, a ... | 2004 | 15528520 |
| characterization of bacterial community diversity in cystic fibrosis lung infections by use of 16s ribosomal dna terminal restriction fragment length polymorphism profiling. | progressive loss of lung function resulting from the inflammatory response to bacterial colonization is the leading cause of mortality in cystic fibrosis (cf) patients. a greater understanding of these bacterial infections is needed to improve lung disease management. as culture-based diagnoses are associated with fundamental drawbacks, we used terminal restriction fragment (t-rf) length polymorphism profiling and 16s rrna clone data to characterize, without prior cultivation, the bacterial comm ... | 2004 | 15528712 |
| a genomic timescale of prokaryote evolution: insights into the origin of methanogenesis, phototrophy, and the colonization of land. | the timescale of prokaryote evolution has been difficult to reconstruct because of a limited fossil record and complexities associated with molecular clocks and deep divergences. however, the relatively large number of genome sequences currently available has provided a better opportunity to control for potential biases such as horizontal gene transfer and rate differences among lineages. we assembled a data set of sequences from 32 proteins (approximately 7600 amino acids) common to 72 species ... | 2004 | 15535883 |
| the bag or the spindle: the cell factory at the time of systems' biology. | genome programs changed our view of bacteria as cell factories, by making them amenable to systematic rational improvement. as a first step, isolated genes (including those of the metagenome), or small gene clusters are improved and expressed in a variety of hosts. new techniques derived from functional genomics (transcriptome, proteome and metabolome studies) now allow users to shift from this single-gene approach to a more integrated view of the cell, where it is more and more considered as a ... | 2004 | 15537427 |
| a genetic screen to isolate type iii effectors translocated into pepper cells during xanthomonas infection. | the bacterial pathogen xanthomonas campestris pv. vesicatoria (xcv) uses a type iii secretion system (ttss) to translocate effector proteins into host plant cells. the ttss is required for xcv colonization, yet the identity of many proteins translocated through this apparatus is not known. we used a genetic screen to functionally identify xcv ttss effectors. a transposon 5 (tn5)-based transposon construct including the coding sequence for the xcv avrbs2 effector devoid of its ttss signal was ran ... | 2004 | 15545602 |
| exploiting thiol modifications. | 2004 | 15547642 | |
| identification and expression profiling of tomato genes differentially regulated during a resistance response to xanthomonas campestris pv. vesicatoria. | the gram-negative bacterium xanthomonas campestris pv. vesicatoria is the causal agent of spot disease in tomato and pepper. plants of the tomato line hawaii 7981 are resistant to race t3 of x. campestris pv. vesicatoria expressing the type iii effector protein avrxv3 and develop a typical hypersensitive response upon bacterial challenge. a combination of suppression subtractive hybridization and microarray analysis identified a large set of cdnas that are induced or repressed during the resista ... | 2004 | 15553246 |
| modulation of swarming and virulence by fatty acids through the rsba protein in proteus mirabilis. | after sensing external signals, proteus mirabilis undergoes a multicellular behavior called swarming which is coordinately regulated with the expression of virulence factors. here we report that exogenously added fatty acids could act as signals to regulate swarming in p. mirabilis. specifically, while oleic acid enhanced swarming, some saturated fatty acids, such as lauric acid, myristic acid, palmitic acid, and stearic acid, inhibited swarming. we also found that expression of hemolysin, which ... | 2004 | 15557604 |
| ornithine decarboxylase gene (caodc1) is specifically induced during tmv-mediated but salicylate-independent resistant response in hot pepper. | a gene encoding putative ornithine decarboxylase (odc) has been isolated by differential screening of a cdna library from the resistant hot pepper (capsicum annuum l.) inoculated with avirulent tobacco mosaic virus (tmv) pathotype p0. in hot pepper plants, transcripts of the caodc1 (c. annuum odc1) gene started to accumulate at 24 h post-inoculation of tmv-p0 and the signal was spread systemically. the transcript level of caodc1 was increased rapidly in a hot pepper resistant to xanthomonas camp ... | 2004 | 15564537 |
| cazfp1, cys2/his2-type zinc-finger transcription factor gene functions as a pathogen-induced early-defense gene in capsicum annuum. | a pepper zinc-finger protein gene, cazfp1 , encoding the cys2/his2-type zinc-finger transcription factor was isolated from pepper leaves inoculated with an avirulent strain bv5-4a of xanthomonas campestris pv. vesicatoria . the cazfp1 protein is a nuclear targeting protein, which functions as a transcriptional regulator. the full-length cazfp1 had no transcriptional activation activity, whereas the c-terminal region of cazfp1 had transactivation activity. the cazfp1 transcripts were constitutive ... | 2004 | 15604723 |
| sensitive and specific detection of xanthomonas campestris pv campestris by pcr using species-specific primers based on hrpf gene sequences. | a sensitive and specific assay was developed to detect bacterial black rot of crucifers caused by xanthomonas campestris pv. campestris (x. c. pv. campestris), in cabbage seed and plant. primers xcf and xcr from hrpf homologous to nolx, host recognition protein, were used to amplify a 525 bp dna fragment. pcr technique was applied to detect the pathogen in naturally infected seed and plant of cabbage. the pcr product was only produced from x. c. pv. campestris among 40 isolates of xanthomonas st ... | 2004 | 15646387 |
| in silico analysis of nonribosomal peptide synthetases of xanthomonas axonopodis pv. citri: identification of putative siderophore and lipopeptide biosynthetic genes. | the genomes of the plant pathogens xanthomonas axonopodis (xac) and xanthomonas campestris (xcc) were analysed with the aim of deducing their ability to produce nonribosomal peptides. nonribosomal peptide synthetase (nrps) genes were identified in two separate loci of xac. while the genes of locus 1 are common to both strains, locus 2 was only found in xac. dissection and phylogenetic analysis of the condensation and thioesterase domains of the nrpss of loci 1 and 2 of xac revealed homology, res ... | 2004 | 15646388 |
| characterization of a novel amylolytic enzyme encoded by a gene from a soil-derived metagenomic library. | it has been estimated that less than 1% of the microorganisms in nature can be cultivated by conventional techniques. thus, the classical approach of isolating enzymes from pure cultures allows the analysis of only a subset of the total naturally occurring microbiota in environmental samples enriched in microorganisms. to isolate useful microbial enzymes from uncultured soil microorganisms, a metagenome was isolated from soil samples, and a metagenomic library was constructed by using the puc19 ... | 2004 | 15574921 |
| complete nucleotide sequence of the conjugative tetracycline resistance plasmid pfbaot6, a member of a group of incu plasmids with global ubiquity. | this study presents the first complete sequence of an incu plasmid, pfbaot6. this plasmid was originally isolated from a strain of aeromonas caviae from hospital effluent (westmorland general hospital, kendal, united kingdom) in september 1997 (g. rhodes, g. huys, j. swings, p. mcgann, m. hiney, p. smith, and r. w. pickup, appl. environ. microbiol. 66:3883-3890, 2000) and belongs to a group of related plasmids with global ubiquity. pfbaot6 is 84,748 bp long and has 94 predicted coding sequences, ... | 2004 | 15574953 |
| associations of the major pseudopilin xpsg with xpsn (gspc) and secretin xpsd of xanthomonas campestris pv. campestris type ii secretion apparatus revealed by cross-linking analysis. | the major pseudopilin xpsg is an essential component of type ii secretion apparatus of xanthomonas campestris pv. campestris. along with other ancillary pseudopilins, it forms a pilus-like structure spanning between cytoplasmic and outer membranes. associations of pseudopilins with non-pseudopilin members of type ii secretion apparatus were not well documented, probably due to their dynamic or unstable nature. in this study, by treating intact cells with a cleavable cross-linker dithiobis(succin ... | 2004 | 15590656 |
| cas3p belongs to a seven-member family of capsule structure designer proteins. | the polysaccharide capsule is the main virulence factor of the basidiomycetous yeast cryptococcus neoformans. four genes (cap10, cap59, cap60, and cap64) essential for capsule formation have been previously identified, although their roles in the biosynthetic pathway remain unclear. a genetic and bioinformatics approach allowed the identification of six cap64-homologous genes, named cas3, cas31, cas32, cas33, cas34, and cas35, in the c. neoformans genome. this gene family is apparently specific ... | 2004 | 15590825 |
| mitochondrial cytochrome c1 is a collapsed di-heme cytochrome. | cytochrome c(1) from mitochondrial complex iii and the di-heme cytochromes c in the corresponding enzyme from epsilon-proteobacteria have so far been considered to represent unrelated cytochromes. a missing link protein discovered in the genome of the hyperthermophilic bacterium aquifex aeolicus, however, provides evidence for a close evolutionary relationship between these two cytochromes. the mono-heme cytochrome c(1) from a. aeolicus contains stretches of strong sequence homology toward the e ... | 2004 | 15591339 |
| the leucine-responsive regulatory protein (lrp) gene for characterization of the relationship among xanthomonas species. | characterization of strains of xanthomonas axonopodis pv. citri by using dna fingerprints that were generated from primers for enterobacterial repetitive intergenic consensus (eric) elements led to the discovery of differential sequences for a leucine-responsive regulatory protein (lrp) gene in two subgroups of strains with different host ranges on citrus spp. dna hybridization and pcr-based assays that used different sets of primers were designed to detect the core sequence, as well as to obtai ... | 2004 | 15023955 |
| structural basis for host recognition by the haemophilus influenzae hia autotransporter. | haemophilus influenzae is an important human pathogen that initiates infection by colonizing the upper respiratory tract. the h. influenzae hia autotransporter is an adhesive protein that promotes adherence to respiratory epithelial cells. hia adhesive activity resides in two homologous binding domains, called hiabd1 and hiabd2. these domains interact with the same host cell receptor, but bind with different affinities. in this report, we describe the crystal structure of the high-affinity hiabd ... | 2004 | 15029242 |
| biosynthesis of udp-glca, a key metabolite for capsular polysaccharide synthesis in the pathogenic fungus cryptococcus neoformans. | udp-glucose dehydrogenase catalyses the conversion of udp-glucose into udp-glca, a critical precursor for glycan synthesis across evolution. we have cloned the gene encoding this important enzyme from the opportunistic pathogen cryptococcus neoformans. in this fungus, udp-glca is required for the synthesis of capsule polysaccharides, which in turn are essential for virulence. the gene was expressed in escherichia coli and the 51.3-kda recombinant protein from wild-type and five mutants was purif ... | 2004 | 15030319 |
| the role of a bifunctional catalase-peroxidase kata in protection of agrobacterium tumefaciens from menadione toxicity. | agrobacterium tumefaciens is an aerobic plant pathogenic bacterium that is exposed to reactive oxygen species produced either as by-products of aerobic metabolism or by the defense systems of host plants. the physiological function of the bifunctional catalase-peroxidase (kata) in the protection of a. tumefaciens from reactive oxygen species other than h(2)o(2) was evaluated in the kata mutant (pb102). unexpectedly, pb102 was highly sensitive to the superoxide generator menadione. the expression ... | 2004 | 15033242 |
| a plant natriuretic peptide-like gene in the bacterial pathogen xanthomonas axonopodis may induce hyper-hydration in the plant host: a hypothesis of molecular mimicry. | background: plant natriuretic peptides (pnps) are systemically mobile molecules that regulate homeostasis at nanomolar concentrations. pnps are up-regulated under conditions of osmotic stress and pnp-dependent processes include changes in ion transport and increases of h2o uptake into protoplasts and whole tissue. presentation of the hypothesis: the bacterial citrus pathogen xanthomonas axonopodis pv. citri str. 306 contains a gene encoding a pnp-like protein. we hypothesise that this bacterial ... | 2004 | 15038836 |
| the lspb protein is involved in the secretion of the lspa1 and lspa2 proteins by haemophilus ducreyi. | the lspa1 and lspa2 proteins of haemophilus ducreyi 35000 are two very large macromolecules that can be detected in concentrated culture supernatant fluid. both of these proteins exhibit homology with the n-terminal region of the bordetella pertussis filamentous hemagglutinin (fha), which is involved in secretion of the latter macromolecule. the lspa2 open reading frame is flanked upstream by a gene, lspb, that encodes a predicted protein with homology to the b. pertussis fhac outer membrane pro ... | 2004 | 15039306 |
| an arabidopsis mutant with altered hypersensitive response to xanthomonas campestris pv. campestris, hxc1, displays a complex pathophenotype. | summary the hxc1 mutant was identified by screening an ems (ethylmethane sulphonate) mutagenized population of arabidopsis col-0 plants for an altered hypersensitive response (hr), after spray inoculation with an hr-inducing isolate of xanthomonas campestris pv. campestris (xcc) (strain 147). the hxc1 mutant shows a susceptible phenotype several days after initiation of the interaction with the avirulent strain. this macroscopically observed phenotype was confirmed by measurement of in planta ba ... | 2004 | 20565620 |
| genetic diversity and pathogenic variation of common blight bacteria (xanthomonas campestris pv. phaseoli and x. campestris pv. phaseoli var. fuscans) suggests pathogen coevolution with the common bean. | abstract common bacterial blight (cbb), caused by xanthomonas campestris pv. phaseoli and x. campestris pv. phaseoli var. fuscans, is one of the most important diseases of common bean (phaseolus vulgaris) in east africa and other bean-growing regions. xanthomonad-like bacteria associated with cbb in malawi and tanzania, east africa, and in wisconsin, u.s., were characterized based on brown pigment production, pathogenicity on common bean, detection with an x. campestris pv. phaseoli- or x. campe ... | 2004 | 18943484 |
| inter-genomic displacement via lateral gene transfer of bacterial trp operons in an overall context of vertical genealogy. | the growing conviction that lateral gene transfer plays a significant role in prokaryote genealogy opens up a need for comprehensive evaluations of gene-enzyme systems on a case-by-case basis. genes of tryptophan biosynthesis are frequently organized as whole-pathway operons, an attribute that is expected to facilitate multi-gene transfer in a single step. we have asked whether events of lateral gene transfer are sufficient to have obscured our ability to track the vertical genealogy that underp ... | 2004 | 15214963 |
| sigi: score-based identification of genomic islands. | genomic islands can be observed in many microbial genomes. these stretches of dna have a conspicuous composition with regard to sequence or encoded functions. genomic islands are assumed to be frequently acquired via horizontal gene transfer. for the analysis of genome structure and the study of horizontal gene transfer, it is necessary to reliably identify and characterize these islands. | 2004 | 15113412 |
| prediction of rna-binding proteins from primary sequence by a support vector machine approach. | elucidation of the interaction of proteins with different molecules is of significance in the understanding of cellular processes. computational methods have been developed for the prediction of protein-protein interactions. but insufficient attention has been paid to the prediction of protein-rna interactions, which play central roles in regulating gene expression and certain rna-mediated enzymatic processes. this work explored the use of a machine learning method, support vector machines (svm) ... | 2004 | 14970381 |
| automated selection of positions determining functional specificity of proteins by comparative analysis of orthologous groups in protein families. | the increasing volume of genomic data opens new possibilities for analysis of protein function. we introduce a method for automated selection of residues that determine the functional specificity of proteins with a common general function (the specificity-determining positions [sdp] prediction method). such residues are assumed to be conserved within groups of orthologs (that may be assumed to have the same specificity) and to vary between paralogs. thus, considering a multiple sequence alignmen ... | 2004 | 14739328 |
| integron diversity in heavy-metal-contaminated mine tailings and inferences about integron evolution. | integrons are horizontal gene transfer (hgt) systems containing elements necessary for site-specific recombination and expression of foreign dna. the overall phylogenetic distribution of integrons and range of genes that can be transferred by integrons are unknown. this report contains an exploration of integrons in an environmental microbial community and an investigation of integron evolution. first, using culture-independent techniques, we explored the diversity of integrons and integron-tran ... | 2004 | 14766601 |
| predicting transmembrane beta-barrels in proteomes. | very few methods address the problem of predicting beta-barrel membrane proteins directly from sequence. one reason is that only very few high-resolution structures for transmembrane beta-barrel (tmb) proteins have been determined thus far. here we introduced the design, statistics and results of a novel profile-based hidden markov model for the prediction and discrimination of tmbs. the method carefully attempts to avoid over-fitting the sparse experimental data. while our model training and sc ... | 2004 | 15141026 |
| from gene trees to organismal phylogeny in prokaryotes: the case of the gamma-proteobacteria. | the rapid increase in published genomic sequences for bacteria presents the first opportunity to reconstruct evolutionary events on the scale of entire genomes. however, extensive lateral gene transfer (lgt) may thwart this goal by preventing the establishment of organismal relationships based on individual gene phylogenies. the group for which cases of lgt are most frequently documented and for which the greatest density of complete genome sequences is available is the gamma-proteobacteria, an ... | 2003 | 12975657 |
| comparative analysis of superintegrons: engineering extensive genetic diversity in the vibrionaceae. | integrons are natural tools for bacterial evolution and innovation. their involvement in the capture and dissemination of antibiotic-resistance genes among gram-negative bacteria is well documented. recently, massive ancestral versions, the superintegrons (sis), were discovered in the genomes of diverse proteobacterial species. si gene cassettes with an identifiable activity encode proteins related to simple adaptive functions, including resistance, virulence, and metabolic activities, and their ... | 2003 | 12618374 |
| recent advances in petroleum microbiology. | recent advances in molecular biology have extended our understanding of the metabolic processes related to microbial transformation of petroleum hydrocarbons. the physiological responses of microorganisms to the presence of hydrocarbons, including cell surface alterations and adaptive mechanisms for uptake and efflux of these substrates, have been characterized. new molecular techniques have enhanced our ability to investigate the dynamics of microbial communities in petroleum-impacted ecosystem ... | 2003 | 14665675 |
| domain architectures of sigma54-dependent transcriptional activators. | 2003 | 12618438 | |
| ccpa-dependent carbon catabolite repression in bacteria. | carbon catabolite repression (ccr) by transcriptional regulators follows different mechanisms in gram-positive and gram-negative bacteria. in gram-positive bacteria, ccpa-dependent ccr is mediated by phosphorylation of the phosphoenolpyruvate:sugar phosphotransferase system intermediate hpr at a serine residue at the expense of atp. the reaction is catalyzed by hpr kinase, which is activated by glycolytic intermediates. in this review, the distribution of ccpa-dependent ccr among bacteria is inv ... | 2003 | 14665673 |
| ancient origin of the tryptophan operon and the dynamics of evolutionary change. | the seven conserved enzymatic domains required for tryptophan (trp) biosynthesis are encoded in seven genetic regions that are organized differently (whole-pathway operons, multiple partial-pathway operons, and dispersed genes) in prokaryotes. a comparative bioinformatics evaluation of the conservation and organization of the genes of trp biosynthesis in prokaryotic operons should serve as an excellent model for assessing the feasibility of predicting the evolutionary histories of genes and oper ... | 2003 | 12966138 |
| hgt-db: a database of putative horizontally transferred genes in prokaryotic complete genomes. | the horizontal gene transfer database (hgt-db) is a genomic database that includes statistical parameters such as g+c content, codon and amino-acid usage, as well as information about which genes deviate in these parameters for prokaryotic complete genomes. under the hypothesis that genes from distantly related species have different nucleotide compositions, these deviated genes may have been acquired by horizontal gene transfer. the current version of the database contains 88 bacterial and arch ... | 2003 | 12519978 |
| versatility of aminoglycosides and prospects for their future. | aminoglycoside antibiotics have had a major impact on our ability to treat bacterial infections for the past half century. whereas the interest in these versatile antibiotics continues to be high, their clinical utility has been compromised by widespread instances of resistance. the multitude of mechanisms of resistance is disconcerting but also illuminates how nature can manifest resistance when bacteria are confronted by antibiotics. this article reviews the most recent knowledge about the mec ... | 2003 | 12857776 |
| tmrdb (tmrna database). | maintained at the university of texas health science center at tyler, texas, the tmrna database (tmrdb) is accessible at the url http://psyche.uthct.edu/dbs/tmrdb/tmrdb.html with mirror sites located at auburn university, auburn, alabama (http://www.ag.auburn.edu/mirror/tmrdb/) and the bioinformatics research center, aarhus, denmark (http://www.bioinf.au.dk/tmrdb/). the tmrdb collects and distributes information relevant to the study of tmrna. in trans-translation, this molecule combines propert ... | 2003 | 12520048 |
| genetic diversity of xanthomonas campestris pv. vitians, the causal agent of bacterial leafspot of lettuce. | abstract bacterial leafspot of lettuce (bls), caused by xanthomonas campes-tris pv. vitians, has become more prevalent in many lettuce-growing areas of the world over the past decade. to gain insight into the nature of these outbreaks, the genetic variation in x. campestris pv. vitians strains from different geographical locations was examined. all strains were first tested for pathogenicity on lettuce plants, and then genetic diversity was assessed using (i) gas-chromatographic analysis of bact ... | 2003 | 18942982 |
| bacteriocin-like substances from tomato race 3 strains of xanthomonas campestris pv. vesicatoria. | abstract tomato race 3 (t3) strains of xanthomonas campestris pv. vesicatoria are antagonistic in vitro to tomato race 1 (t1) strains of the bacterium. all t1 strains and 11 strains of other x. campestris pathovars tested were inhibited by t3 strains. sensitivity of tomato race 2 (t2) strains was variable. no strains from other bacterial genera tested were inhibited. cell-free filtrates from t3 strains were inhibitory to sensitive strains. the inhibitory activity of these filtrates was lost afte ... | 2003 | 18944070 |
| diversity among strains of xanthomonas campestris pv. vitians from lettuce. | abstract diversity in host range, pathogenicity, phenotypic characteristics, repetitive extragenic palindromic polymerase chain reaction (rep-pcr) profiles, and sequence of the 16s-23s rdna spacer region was examined among 44 xanthomonas strains isolated from lettuce. forty-two of the strains were divided into two groups, designated a and b. seventy percent were group a, and most of the remaining strains including a reference strain (lmg 938) were group b. group a strains induced both local and ... | 2003 | 18944158 |
| a technique for precise inoculation of the internal phyllosphere of cotton with xanthomonas campestris pv. malvacearum. | abstract a technique was developed to inoculate uniformly and gently the internal phyllosphere from the upper surface of cotton leaves with the phytopathogenic bacterium xanthomonas campestris pv. malvacearum. the inoculum consisted of 2 to 3 x 10(7) cfu/ml in caco(3)-saturated sterile distilled water containing 0.02%, vol/vol, of the wetting agent silwet l-77. a custom-made inoculation apparatus was employed to immerse a circular area of the adaxial surface of a leaf in inoculum for 90 s. this ... | 2003 | 18944317 |
| isolation and characterization of rhizobacteria from composts that suppress the severity of bacterial leaf spot of radish. | abstract composts can induce systemic resistance in plants to disease. unfortunately, the degree of resistance induced seems highly variable and the basis for this effect is not understood. in this work, only 1 of 79 potting mixes prepared with different batches of mature, stabilized composts produced from several different types of solid wastes suppressed the severity of bacterial leaf spot of radish caused by xanthomonas campestris pv. armoraciae compared with disease on plants produced in a n ... | 2003 | 18944329 |
| detecting and differentiating acremonium implicatum: developing a pcr-based method for an endophytic fungus associated with the genus brachiaria. | summary brachiaria is a pan-tropical genus of grasses with about 100 species. the fungus acremonium implicatum can develop an endophytic association that is mutually beneficial with brachiaria species. we developed a polymerase chain reaction (pcr)-based method by first amplifying dna from a. implicatum isolates using the random amplified polymorphic dna (rapd) technique with arbitrary 10-mer primers. a 500-bp pcr product, amplified with primer opak-10 and common to a. implicatum isolates, was s ... | 2003 | 20569370 |
| genotypic analysis of xylella fastidiosa isolates from different hosts using sequences homologous to the xanthomonas rpf genes. | summary this is the first report of a genotypic analysis of the phytopathogenic bacteria xylella fastidiosa (xf) using differences within intra- and intergenic regions of pathogenic genes. orthologous sequences from the genome of xf were identified for genes involved in the regulation of pathogenicity factors (rpf) from xanthomonas campestris pv. campestris (xcc). while the rpf genes were conserved, the chromosomal region revealed differences in gene sizes and intergenic spacings and a major tra ... | 2003 | 20569393 |
| characterization of two antagonistic strains of rahnella aquatilis isolated from soil in egypt. | in an attempt to obtain biological control agents for controlling bacterial spot of cucumber, over 250 bacterial strains were isolated from agricultural soil samples, collected from different localities in giza governorate (egypt) and screened for in vitro antibiosis towards xanthomonas campestris. only 2 strains showed antagonistic activity. they and their culture filtrates restricted the growth of a number of g- and g(+)-indicator bacteria. on chrome azurol s agar, both strains exhibited a mar ... | 2003 | 15058195 |
| [identification and cloning of a novel gene involved in eps biosynthesis of xanthomonas campestris pv. campestris]. | xanthomonas campestris pv. campestris ( xcc), causative agent of the black rot disease of cruciferous crops worldwide, produces large amount of extracellular polysaccharide( eps), which has found wide applications in industry. in order to clone genes involved in eps biosynthesis, xcc wild-type strain 8004 was mutagenized with transposon tn5gus a5, and a number of eps-defective mutants were isolated. the tn5gusa5 insertion sites in the mutants were analyzed by using thermal asymmetric interlaced ... | 2003 | 15971576 |
| selective alpha-glucosylation of eugenol by alpha-glucosyl transfer enzyme of xanthomonas campestris wu-9701. | for one-step enzymatic synthesis of eugenyl alpha-glucoside as a promising pro-drug for a hair restorer and a derivative of spices, selective alpha-glucosylation of eugenol was carried out using the alpha-glucosyl transfer enzyme of xanthomonas campestris wu-9701. when 130 micromol eugenol and crude enzyme showing 1.0 unit of alpha-glucosyl transfer activity were shaken in 2 ml of 10 mm h3bo3-naoh-kcl buffer (ph 8.0) containing 1.2 m maltose as a glucosyl donor at 40 degrees c, only one form of ... | 2003 | 16233510 |
| molecular genetic analyses of potential beta-galactosidase genes in xanthomonas campestris. | xanthomonas campestris pv. campestris, which displays no significant beta-1,4-d-galactopyranosidase activity, has three annotated beta-galactosidase genes in the sequenced genome, designated gala, galb and galc herein. gala and galb are similar to glycosyl hydrolase (gh) family 2 enzymes, including escherichia coli lacz. gala and galb cannot express detectable activity even after being cloned in-frame and driven by the vector's promoter. galc is a gh35 enzyme homologous to the xanthomonas axonop ... | 2003 | 15153767 |
| whole genome shotgun sequencing guided by bioinformatics pipelines--an optimized approach for an established technique. | while the sequencing of bacterial genomes has become a routine procedure at major sequencing centers, there are still a number of genome projects at small- or medium-size facilities. for these facilities a maximum of control over sequencing, assembling and finishing is essential. at the same time, facilities have to be able to co-operate at minimum costs for the overall project. we have established a pipeline for the distributed sequencing of alcanivorax borkumensis sk2, azoarcus sp. bh72, clavi ... | 2003 | 14651855 |
| comparison of two xanthomonas campestris pathovar campestris genomes revealed differences in their gene composition. | for the xanthomonas campestris pathovar campestris wild-type strain b100 a plasmid-based clone library was constructed. the plasmids carried chromosomal fragments of 3-4 kb in size that were tagged in vitro with the artificial transposon kan-2. more than 3000 of the transposon target sites were characterized by dna sequencing. the sequences obtained were compared to the recently published genome of xanthomonas campestris pathovar campestris strain atcc 33913. most of the sequenced clones derived ... | 2003 | 14651861 |
| genomic approaches in xanthomonas campestris pv. vesicatoria allow fishing for virulence genes. | xanthomonas campestris pv. vesicatoria is an economically important pathogen of pepper and tomato and has been established as a model organism to study bacterial infection strategies. in the last two decades, intensive genetic and molecular analyses led to the isolation of many genes that play a role in the intimate molecular relationship with the host plant. essential for pathogenicity is a type iii protein secretion system, which delivers bacterial effector proteins into the host cell. current ... | 2003 | 14651862 |
| new connections in the prokaryotic toxin-antitoxin network: relationship with the eukaryotic nonsense-mediated rna decay system. | several prokaryotic plasmids maintain themselves in their hosts by means of diverse post-segregational cell killing systems. recent findings suggest that chromosomally encoded copies of toxins and antitoxins of post-segregational cell killing systems - such as the rele system - might function as regulatory switches under stress conditions. the rele toxin cleaves ribosome-associated transcripts, whereas another post-segregational cell killing toxin, pare, functions as a gyrase inhibitor. | 2003 | 14659018 |
| metagenome survey of biofilms in drinking-water networks. | most naturally occurring biofilms contain a vast majority of microorganisms which have not yet been cultured, and therefore we have little information on the genetic information content of these communities. therefore, we initiated work to characterize the complex metagenome of model drinking water biofilms grown on rubber-coated valves by employing three different strategies. first, a sequence analysis of 650 16s rrna clones indicated a high diversity within the biofilm communities, with the ma ... | 2003 | 14660379 |
| concomitant induction of systemic resistance to pseudomonas syringae pv. lachrymans in cucumber by trichoderma asperellum (t-203) and accumulation of phytoalexins. | most studies on the reduction of disease incidence in soil treated with trichoderma asperellum have focused on microbial interactions rather than on plant responses. this study presents conclusive evidence for the induction of a systemic response against angular leaf spot of cucumber (pseudomonas syringae pv. lachrymans) following application of t. asperellum to the root system. to ascertain that t. asperellum was the only microorganism present in the root milieu, plants were grown in an aseptic ... | 2003 | 14660384 |
| multiple hormones act sequentially to mediate a susceptible tomato pathogen defense response. | phytohormones regulate plant responses to a wide range of biotic and abiotic stresses. how a limited number of hormones differentially mediate individual stress responses is not understood. we have used one such response, the compatible interaction of tomato (lycopersicon esculentum) and xanthomonas campestris pv vesicatoria (xcv), to examine the interactions of jasmonic acid (ja), ethylene, and salicylic acid (sa). the role of ja was assessed using an antisense allene oxide cyclase transgenic l ... | 2003 | 14551324 |
| involvement of an inducible fructose phosphotransferase operon in streptococcus gordonii biofilm formation. | oral streptococci, such as streptococcus gordonii, are the predominant early colonizers that initiate biofilm formation on tooth surfaces. investigation of an s. gordonii::tn917-lac biofilm-defective mutant isolated by using an in vitro biofilm formation assay showed that the transposon insertion is near the 3' end of an open reading frame (orf) encoding a protein homologous to streptococcus mutans fruk. three genes, frur, fruk, and frui, were predicted to encode polypeptides that are part of th ... | 2003 | 14563858 |
| cadmium-induced adaptive resistance and cross-resistance to zinc in xanthomonas campestris. | cadmium (cd) and zinc (zn) are environmental pollutants affecting both soil and water. the toxicity resulting from the exposure of xanthomonas campestris, a soil bacterium and plant pathogen, to these metals was investigated. pretreatment of x. campestris with sub-lethal concentrations of cd induced adaptive protection against subsequent exposure to lethal doses of cd. moreover, cd-induced cells also showed cross-resistance to lethal concentrations of zn. these induced protections required newly ... | 2003 | 14570280 |
| high throughput virus-induced gene silencing implicates heat shock protein 90 in plant disease resistance. | virus-induced gene silencing was used to assess the function of random nicotiana benthamiana cdnas in disease resistance. out of 4992 cdnas tested from a normalized library, there were 79 that suppressed a hypersensitive response (hr) associated with pto-mediated resistance against pseudomonas syringae. however, only six of these clones blocked the pto-mediated suppression of p.syringae growth. the three clones giving the strongest loss of pto resistance had inserts corresponding to hsp90 and al ... | 2003 | 14592968 |
| identification and characterization of a unique adenosine kinase from mycobacterium tuberculosis. | adenosine kinase (ak) is a purine salvage enzyme that catalyzes the phosphorylation of adenosine to amp. in mycobacterium tuberculosis, ak can also catalyze the phosphorylation of the adenosine analog 2-methyladenosine (methyl-ado), the first step in the metabolism of this compound to an active form. purification of ak from m. tuberculosis yielded a 35-kda protein that existed as a dimer in its native form. adenosine (ado) was preferred as a substrate at least 30-fold (km = 0.8 +/- 0.08 microm) ... | 2003 | 14594827 |
| flagellin glycosylation island in pseudomonas syringae pv. glycinea and its role in host specificity. | the deduced amino acid sequences of the flagellins of pseudomonas syringae pv. tabaci and p. syringae pv. glycinea are identical; however, their abilities to induce a hypersensitive reaction are clearly different. the reason for the difference seems to depend on the posttranslational modification of the flagellins. to investigate the role of this posttranslational modification in the interactions between plants and bacterial pathogens, we isolated genes that are potentially involved in the postt ... | 2003 | 14594840 |
| phya, a secreted protein of xanthomonas oryzae pv. oryzae, is required for optimum virulence and growth on phytic acid as a sole phosphate source. | xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. we have identified a novel virulence deficient mutant (bxo1691) of x. oryzae pv. oryzae that has a tn5 insertion in an open reading frame (phya; putative phytase a) encoding a 373-amino acid (aa) protein containing a 28-aa predicted signal peptide. extracellular protein profiles revealed that a 38-kda band is absent in phya mutants as compared with phya+ strains. a blast search with phya and its deduced polype ... | 2003 | 14601665 |
| activity of class iii peroxidases in the defense of cotton to bacterial blight. | cotton cotyledons displayed a hypersensitive reaction (hr) in the cultivar réba b50 after infiltration with the avirulent race 18 from xanthomonas campestris pv. malvacearum. two sets of peroxidases were associated with the hr time course. early but transient accumulation of peroxidase in material encapsulating the bacteria in intercellular areas was observed by immunocytochemistry at 3 h postinfection and coincided with the oxidative burst. total guaiacol-peroxidase activity was highly increase ... | 2003 | 14601671 |
| gene essentiality determines chromosome organisation in bacteria. | in escherichia coli and bacillus subtilis, essentiality, not expressivity, drives the distribution of genes between the two replicating strands. although essential genes tend to be coded in the leading replicating strand, the underlying selective constraints and the evolutionary extent of these findings have still not been subject to comparative studies. here, we extend our previous analysis to the genomes of low g + c firmicutes and gamma-proteobacteria, and in a second step to all sequenced ba ... | 2003 | 14602916 |
| xanthomonas type iii effector xopd targets sumo-conjugated proteins in planta. | xanthomonas campestris pathovar vesicatoria (xcv) uses the type iii secretion system (ttss) to inject effector proteins into cells of solanaceous plants during pathogenesis. a number of xcv ttss effectors have been identified; however, their function in planta remains elusive. here, we provide direct evidence for a functional role for a phytopathogenic bacterial ttss effector in planta by demonstrating that the xcv effector xopd encodes an active cysteine protease with plant-specific sumo substr ... | 2003 | 14617166 |
| identification and characterization of genes required for biosynthesis and transport of the siderophore vibrioferrin in vibrio parahaemolyticus. | in response to low iron availability, vibrio parahaemolyticus synthesizes and secretes a polyhydroxycarboxylate-type siderophore vibrioferrin which is composed of 1 mol each of 2-ketoglutaric acid, l-alanine, ethanolamine, and citric acid. we have previously reported the cloning and characterization of the pvua gene, which encodes the 78-kda outer membrane receptor protein for ferric vibrioferrin. in this study, nine genes involved in the biosynthesis and transport of vibrioferrin have been iden ... | 2003 | 14617658 |
| folm, a new chromosomally encoded dihydrofolate reductase in escherichia coli. | escherichia coli (thya deltafola) mutants are viable and can grow in minimal medium when supplemented with thymidine alone. here we present evidence from in vivo and in vitro studies that the ydgb gene determines an alternative dihydrofolate reductase that is related to the trypanosomatid pteridine reductases. we propose to rename this gene folm. | 2003 | 14617668 |
| fimx, a multidomain protein connecting environmental signals to twitching motility in pseudomonas aeruginosa. | twitching motility is a form of surface translocation mediated by the extension, tethering, and retraction of type iv pili. three independent tn5-b21 mutations of pseudomonas aeruginosa with reduced twitching motility were identified in a new locus which encodes a predicted protein of unknown function annotated pa4959 in the p. aeruginosa genome sequence. complementation of these mutants with the wild-type pa4959 gene, which we designated fimx, restored normal twitching motility. fimx mutants we ... | 2003 | 14645265 |
| xopc and xopj, two novel type iii effector proteins from xanthomonas campestris pv. vesicatoria. | pathogenicity of the gram-negative plant pathogen xanthomonas campestris pv. vesicatoria depends on a type iii secretion (tts) system which translocates bacterial effector proteins into the plant cell. previous transcriptome analysis identified a genome-wide regulon of putative virulence genes that are coexpressed with the tts system. in this study, we characterized two of these genes, xopc and xopj. both genes encode xanthomonas outer proteins (xops) that were shown to be secreted by the tts sy ... | 2003 | 14645268 |
| novel type of specialized transduction for ctx phi or its satellite phage rs1 mediated by filamentous phage vgj phi in vibrio cholerae. | the main virulence factor of vibrio cholerae, the cholera toxin, is encoded by the ctxab operon, which is contained in the genome of the lysogenic filamentous phage ctx phi. this phage transmits ctxab genes between v. cholerae bacterial populations that express toxin-coregulated pilus (tcp), the ctx phi receptor. in investigating new forms of ctxab transmission, we found that v. cholerae filamentous phage vgj phi, which uses the mannose-sensitive hemagglutinin (msha) pilus as a receptor, transmi ... | 2003 | 14645284 |
| legume symbiotic nitrogen fixation by beta-proteobacteria is widespread in nature. | following the initial discovery of two legume-nodulating burkholderia strains (l. moulin, a. munive, b. dreyfus, and c. boivin-masson, nature 411:948-950, 2001), we identified as nitrogen-fixing legume symbionts at least 50 different strains of burkholderia caribensis and ralstonia taiwanensis, all belonging to the beta-subclass of proteobacteria, thus extending the phylogenetic diversity of the rhizobia. r. taiwanensis was found to represent 93% of the mimosa isolates in taiwan, indicating that ... | 2003 | 14645288 |
| a suppressor of the menadione-hypersensitive phenotype of a xanthomonas campestris pv. phaseoli oxyr mutant reveals a novel mechanism of toxicity and the protective role of alkyl hydroperoxide reductase. | we isolated menadione-resistant mutants of xanthomonas campestris pv. phaseoli oxyr (oxyr(xp)). the oxyrr2(xp) mutant was hyperresistant to the superoxide generators menadione and plumbagin and was moderately resistant to h(2)o(2) and tert-butyl hydroperoxide. analysis of enzymes involved in oxidative-stress protection in the oxyrr2(xp) mutant revealed a >10-fold increase in ahpc and ahpf levels, while the levels of superoxide dismutase (sod), catalase, and the organic hydroperoxide resistance p ... | 2003 | 12591894 |
| attenuated virulence of a burkholderia cepacia type iii secretion mutant in a murine model of infection. | type iii secretion systems are utilized by a number of gram-negative bacterial pathogens to deliver virulence-associated proteins into host cells. using a pcr-based approach, we identified homologs of type iii secretion genes in the gram-negative bacterium burkholderia cepacia, an important pulmonary pathogen in immunocompromised patients and patients with cystic fibrosis. one of the genes, designated bscn, encodes a member of a family of atp-binding proteins believed to generate energy driving ... | 2003 | 12595458 |
| the pair of bacteriophytochromes from agrobacterium tumefaciens are histidine kinases with opposing photobiological properties. | bacteriophytochrome photoreceptors (bphps) are a family of phytochrome-like sensor kinases that help a wide variety of bacteria respond to their light environment. in agrobacterium tumefaciens, a unique pair of bphps with potentially opposing roles in light sensing are present. both atbphps contain an n-terminal chromophore-binding domain that covalently attaches a biliverdin chromophore. whereas atbphp1 assumes a pr ground state, atbphp2 is unusual in that it assumes a pfr ground state that is ... | 2003 | 12604773 |
| origin and evolution of circadian clock genes in prokaryotes. | regulation of physiological functions with approximate daily periodicity, or circadian rhythms, is a characteristic feature of eukaryotes. until recently, cyanobacteria were the only prokaryotes reported to possess circadian rhythmicity. it is controlled by a cluster of three genes: kaia, kaib, and kaic. using sequence data of approximately 70 complete prokaryotic genomes from the various public depositories, we show here that the kai genes and their homologs have quite a different evolutionary ... | 2003 | 12604787 |
| excision and integration of cassettes by an integron integrase of nitrosomonas europaea. | we found in the environmental strain nitrosomonas europaea a chromosomal integron-like structure with an integrase gene, inti(neu). we have tested the capacity of the intineu integrase to excise and integrate several resistance gene cassettes. the results allow us to consider intineu a new functional integron integrase. | 2003 | 12618471 |
| the rhomboids: a nearly ubiquitous family of intramembrane serine proteases that probably evolved by multiple ancient horizontal gene transfers. | the rhomboid family of polytopic membrane proteins shows a level of evolutionary conservation unique among membrane proteins. they are present in nearly all the sequenced genomes of archaea, bacteria and eukaryotes, with the exception of several species with small genomes. on the basis of experimental studies with the developmental regulator rhomboid from drosophila and the aara protein from the bacterium providencia stuartii, the rhomboids are thought to be intramembrane serine proteases whose ... | 2003 | 12620104 |
| lateral gene transfer and ancient paralogy of operons containing redundant copies of tryptophan-pathway genes in xylella species and in heterocystous cyanobacteria. | tryptophan-pathway genes that exist within an apparent operon-like organization were evaluated as examples of multi-genic genomic regions that contain phylogenetically incongruous genes and coexist with genes outside the operon that are congruous. a seven-gene cluster in xylella fastidiosa includes genes encoding the two subunits of anthranilate synthase, an aryl-coa synthetase, and trpr. a second gene block, present in the anabaena/nostoc lineage, but not in other cyanobacteria, contains a near ... | 2003 | 12620124 |
| xanosporic acid, an intermediate in bacterial degradation of the fungal phototoxin cercosporin. | the red fungal perylenequinone phototoxin cercosporin is oxidized by xanthomonas campestris pv zinniae to a non-toxic, unstable green metabolite xanosporic acid, identified via its lactone as 1,12-bis(2'r-hydroxypropyl)-4,9-dihydroxy-6,7-methylenedioxy-11-methoxy-3-oxaperylen-10h-10-one-2-carboxylic acid. xanosporolactone was isolated in approximately 2:1 ratio of m:p atropisomers. | 2003 | 12620324 |
| construction and screening of metagenomic libraries derived from enrichment cultures: generation of a gene bank for genes conferring alcohol oxidoreductase activity on escherichia coli. | enrichment of microorganisms with special traits and the construction of metagenomic libraries by direct cloning of environmental dna have great potential for identifying genes and gene products for biotechnological purposes. we have combined these techniques to isolate novel genes conferring oxidation of short-chain (c(2) to c(4)) polyols or reduction of the corresponding carbonyls. in order to favor the growth of microorganisms containing the targeted genes, samples collected from four differe ... | 2003 | 12620823 |
| prokaryotic homologs of the eukaryotic 3-hydroxyanthranilate 3,4-dioxygenase and 2-amino-3-carboxymuconate-6-semialdehyde decarboxylase in the 2-nitrobenzoate degradation pathway of pseudomonas fluorescens strain ku-7. | the 2-nitrobenzoic acid degradation pathway of pseudomonas fluorescens strain ku-7 proceeds via a novel 3-hydroxyanthranilate intermediate. in this study, we cloned and sequenced a 19-kb dna locus of strain ku-7 that encompasses the 3-hydroxyanthranilate meta-cleavage pathway genes. the gene cluster, designated nbaexhjigfcdr, is organized tightly and in the same direction. the nbac and nbad gene products were found to be novel homologs of the eukaryotic 3-hydroxyanthranilate 3,4-dioxygenase and ... | 2003 | 12620844 |
| the 1.6-a crystal structure of the class of chaperones represented by escherichia coli hsp31 reveals a putative catalytic triad. | heat shock proteins (hsps) play essential protective roles under stress conditions by preventing the formation of protein aggregates and degrading misfolded proteins. echsp31, the yedu (hcha) gene product, is a representative member of a family of chaperones that alleviates protein misfolding by interacting with early unfolding intermediates. the 1.6-a crystal structure of the echsp31 dimer reveals a system of hydrophobic patches, canyons, and grooves, which may stabilize partially unfolded subs ... | 2003 | 12621151 |
| expression of the apyrase-like apy1 genes in roots of medicago truncatula is induced rapidly and transiently by stress and not by sinorhizobium meliloti or nod factors. | the model legume medicago truncatula contains at least six apyrase-like genes, five of which (mtapy1;1, mtapy1;2, mtapy1;3, mtapy1;4, and mtapy1;5) are members of a legume-specific family, whereas a single gene (mtapy2) has closer homologs in arabidopsis. phylogenetic analysis has revealed that the proteins encoded by these two plant gene families are more similar to yeast (saccharomyces cerevisiae) gda1 and to two proteins encoded by newly described mammalian genes (enp5 and 6) than they are to ... | 2003 | 12644663 |
| involvement of tonb-exbbd1d2 operon in infection of xanthomonas campestris phage phi l7. | phi l7 is a lytic bacteriophage infecting xanthomonas campestris pv. campestris, a gram-negative bacterium producing xanthan gum and causing black rot in crucifers. a mutant resistant to phi l7 was isolated by tn5 mutagenesis. sequence analysis indicated that the gene responsible for the mutation is tonb encoding an inner membrane protein previously shown to be required for iron uptake and pathogenesis. this gene is clustered with three other genes, tonb-exbb-exbd1-exbd2. results of insertional ... | 2003 | 12646254 |
| expression of peroxidase-like genes, h2o2 production, and peroxidase activity during the hypersensitive response to xanthomonas campestris pv. vesicatoria in capsicum annuum. | pepper ascorbate peroxidase-like (capoa1), thioredoxin peroxidase-like (capot1), and peroxidase-like (capo1) clones were isolated from pepper leaves inoculated with avirulent strain bv5-4a of xanthomonas campestris pv. vesicatoria. capoa1, capot1, and capo1 mrna disappeared 18 to 30 h after the bacterial infection when the hypersensitive response (hr) was visible. in contrast, peroxidase activity reached a peak at 18 h after infection and then declined at 24 and 30 h when h2o2 accumulation level ... | 2003 | 12650451 |
| geobacter sulfurreducens has two autoregulated lexa genes whose products do not bind the reca promoter: differing responses of lexa and reca to dna damage. | the escherichia coli lexa protein was used as a query sequence in tblastn searches to identify the lexa gene of the delta-proteobacterium geobacter sulfurreducens from its genome sequence. the results of the search indicated that g. sulfurreducens has two independent lexa genes designated lexa1 and lexa2. a copy of a dinb gene homologue, which in e. coli encodes dna polymerase iv, is present downstream of each lexa gene. reverse transcription-pcr analyses demonstrated that, in both cases, lexa a ... | 2003 | 12670973 |
| pseudomonas syringae exchangeable effector loci: sequence diversity in representative pathovars and virulence function in p. syringae pv. syringae b728a. | pseudomonas syringae is a plant pathogen whose pathogenicity and host specificity are thought to be determined by hop/avr effector proteins injected into plant cells by a type iii secretion system. p. syringae pv. syringae b728a, which causes brown spot of bean, is a particularly well-studied strain. the type iii secretion system in p. syringae is encoded by hrp (hypersensitive response and pathogenicity) and hrc (hrp conserved) genes, which are clustered in a pathogenicity island with a tripart ... | 2003 | 12670984 |
| isolation and antifungal and antioomycete activities of aerugine produced by pseudomonas fluorescens strain mm-b16. | the bacterial strain mm-b16, which showed strong antifungal and antioomycete activity against some plant pathogens, was isolated from a mountain forest soil in korea. based on the physiological and biochemical characteristics and 16s ribosomal dna sequence analysis, the bacterial strain mm-b16 was identical to pseudomonas fluorescens. an antibiotic active against colletotrichum orbiculare and phytophthora capsici in vitro and in vivo was isolated from the culture filtrates of p. fluorescens stra ... | 2003 | 12676678 |
| type ii protein secretion in pseudomonas aeruginosa: the pseudopilus is a multifibrillar and adhesive structure. | the type ii secretion pathway of pseudomonas aeruginosa is involved in the extracellular release of various toxins and hydrolytic enzymes such as exotoxin a and elastase. this pathway requires the function of a macromolecular complex called the xcp secreton. the xcp secreton shares many features with the machinery involved in type iv pilus assembly. more specifically, it involves the function of five pilin-like proteins, the xcpt-x pseudopilins. we show that, upon overexpression, the xcpt pseudo ... | 2003 | 12700254 |
| efficient synthesis of a heptasaccharide, the repeating unit of the o-chain lipopolysaccharide produced by xanthomonas campestris strain 642. | alpha-l-rhap-(1-->3)-alpha-l-rhap-(1-->2)-alpha-l-rhap-(1-->3)-[beta-d-xylp-(1-->2)-][beta-d-xylp-(1-->4)-]alpha-l-rhap-(1-->3)-alpha-l-rhap, the repeating unit of the o-chain lipopolysaccharide produced by xanthomonas campestris strain 642 was synthesized as its methyl glycoside via 3-o-selective glycosylation of methyl alpha-l-rhamnopyranosyl-(1-->3)-2,4-di-o-benzoyl-alpha-l-rhamnopyranoside (9) with 2,3,4-tri-o-benzoyl-alpha-l-rhamnopyranosyl-(1-->3)-2,4-di-o-benzoyl-alpha-l-rhamnopyranosyl-( ... | 2003 | 12706967 |
| characterization of the xanthomonas axonopodis pv. glycines hrp pathogenicity island. | we sequenced an approximately 29-kb region from xanthomonas axonopodis pv. glycines that contained the hrp type iii secretion system, and we characterized the genes in this region by tn3-gus mutagenesis and gene expression analyses. from the region, hrp (hypersensitive response and pathogenicity) and hrc (hrp and conserved) genes, which encode type iii secretion systems, and hpa (hrp-associated) genes were identified. the characteristics of the region, such as the presence of many virulence gene ... | 2003 | 12730176 |
| quorum sensing in plant-pathogenic bacteria. | quorum sensing (qs) allows bacteria to assess their local population density and/or physical confinement via the secretion and detection of small, diffusible signal molecules. this review describes how phytopathogenic bacteria have incorporated qs mechanisms into complex regulatory cascades that control genes for pathogenicity and colonization of host surfaces. traits regulated by qs include the production of extracellular polysaccharides, degradative enzymes, antibiotics, siderophores, and pigm ... | 2003 | 12730390 |