Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| identification of quorum-quenching n-acyl homoserine lactonases from bacillus species. | a range of gram-negative bacterial species use n-acyl homoserine lactone (ahl) molecules as quorum-sensing signals to regulate different biological functions, including production of virulence factors. ahl is also known as an autoinducer. an autoinducer inactivation gene, aiia, coding for an ahl lactonase, was cloned from a bacterial isolate, bacillus sp. strain 240b1. here we report identification of more than 20 bacterial isolates capable of enzymatic inactivation of ahls from different source ... | 2002 | 11916693 |
| a putative three-dimensional targeting motif of polygalacturonase (peha), a protein secreted through the type ii (gsp) pathway in erwinia carotovora. | intramolecular information specifying protein secretion through the type ii (gsp) pathway of gram-negative bacteria was investigated. two regions of the polygalacturonase (peha) of erwinia carotovora containing residues proposed to be included in a targeting motif were located, one close to the c-terminus between residues 342 and 369 and another between residues 84 and 135 in the large central loops. the regions were required together to promote secretion. further residues in the middle of the p ... | 2002 | 11929517 |
| genetic control of quorum-sensing signal turnover in agrobacterium tumefaciens. | a signal turnover system is an essential component of many genetic regulatory mechanisms. the best-known example is the ubiquitin-dependent protein degradation system that exists in many organisms. we found that agrobacterium tumefaciens adopts a unique signal turnover system to control exiting from a quorum-sensing mode. a. tumefaciens regulates ti plasmid conjugal transfer by a quorum-sensing signal, n-3-oxo-octanoyl homoserine lactone (3oc8hsl), also known as agrobacterium autoinducer. by usi ... | 2002 | 11930013 |
| [study of population dissociation of collection strains of erwinia carotovora]. | unusual dissociants of erwinia carotovora subsp. atroseptica (eat) population that emerge with high frequency (18-94%) during long-term storage of cultures were found. the dissociants (poe-phenotype) differ from parental forms by slow growth and long development of the colour of colonies on emb agar though they are not lac-mutants. more than 60% of poe-mutants of strain eat 39a are characterized by 8- and 150-fold decrease of stability to erythromycin and oleandomicin, correspondingly. they are ... | 2002 | 11944340 |
| rhodospirillum centenum utilizes separate motor and switch components to control lateral and polar flagellum rotation. | rhodospirillum centenum is a purple photosynthetic bacterium that is capable of differentiating from vibrioid swimming cells that contain a single polar flagellum into rod-shaped swarming cells that have a polar flagellum plus numerous lateral flagella. microscopic studies have demonstrated that the polar flagellum is constitutively present and that the lateral flagella are found only when the cells are grown on solidified or viscous medium. in this study, we demonstrated that r. centenum contai ... | 2002 | 11948156 |
| ocatin. a novel tuber storage protein from the andean tuber crop oca with antibacterial and antifungal activities. | the most abundant soluble tuber protein from the andean crop oca (oxalis tuberosa mol.), named ocatin, has been purified and characterized. ocatin accounts for 40% to 60% of the total soluble oca tuber proteins, has an apparent molecular mass of 18 kd and an isoelectric point of 4.8. this protein appears to be found only in tubers and is accumulated only within the cells of the pith and peridermis layers (peel) of the tuber as it develops. ocatin inhibits the growth of several phytopathogenic ba ... | 2002 | 11950978 |
| genomic analysis of the f3031 brazilian purpuric fever clone of haemophilus influenzae biogroup aegyptius by pcr-based subtractive hybridization. | pcr-based subtractive genome hybridization produced clones harboring inserts present in brazilian purpuric fever (bpf) prototype strain f3031 but absent in noninvasive haemophilus influenzae biogroup aegyptius isolate f1947. some of these inserts have no matches in the genbank database, while others are similar to genes encoding either known or hypothetical proteins. one insert represents a 2.3-kb locus with similarity to a thermotoga maritima hypothetical protein, while another is part of a 7.6 ... | 2002 | 11953414 |
| response of endophytic bacterial communities in potato plants to infection with erwinia carotovora subsp. atroseptica. | the term endophyte refers to interior colonization of plants by microorganisms that do not have pathogenic effects on their hosts, and various endophytes have been found to play important roles in plant vitality. in this study, cultivation-independent terminal restriction fragment length polymorphism analysis of 16s ribosomal dna directly amplified from plant tissue dna was used in combination with molecular characterization of isolates to examine the influence of plant stress, achieved by infec ... | 2002 | 11976096 |
| high-density microarray of small-subunit ribosomal dna probes. | ribosomal dna sequence analysis, originally conceived as a way to provide a universal phylogeny for life forms, has proven useful in many areas of biological research. some of the most promising applications of this approach are presently limited by the rate at which sequences can be analyzed. as a step toward overcoming this limitation, we have investigated the use of photolithography chip technology to perform sequence analyses on amplified small-subunit rrna genes. the genechip (affymetrix co ... | 2002 | 11976131 |
| advancing the quorum in pseudomonas aeruginosa: mvat and the regulation of n-acylhomoserine lactone production and virulence gene expression. | pseudomonas aeruginosa regulates the production of many exoproteins and secondary metabolites via a hierarchical quorum-sensing cascade through lasr and rhlr and their cognate signal molecules n-(3-oxododecanoyl)-l-homoserine lactone (3o-c12-hsl) and n-(butanoyl)-l-homoserine lactone (c4-hsl). in this study, we found that transcription of the quorum sensing-regulated genes leca (coding for pa-il lectin), lasb (coding for elastase), and rpos appeared to be growth phase dependent and their express ... | 2002 | 11976285 |
| pehn, a polygalacturonase homologue with a low hydrolase activity, is coregulated with the other erwinia chrysanthemi polygalacturonases. | erwinia chrysanthemi 3937 secretes an arsenal of pectinolytic enzymes, including at least eight endo-pectate lyases encoded by pel genes, which play a major role in the soft-rot disease caused by this bacterium on various plants. e. chrysanthemi also produces some hydrolases that cleave pectin. three adjacent hydrolase genes, pehv, pehw, and pehx, encoding exo-poly-alpha-d-galacturonosidases, have been characterized. these enzymes liberate digalacturonides from the nonreducing end of pectin. we ... | 2002 | 11976295 |
| sample sequencing of a selected region of the genome of erwinia carotovora subsp. atroseptica reveals candidate phytopathogenicity genes and allows comparison with escherichia coli. | genome sequencing is making a profound impact on microbiology. currently, however, only one plant pathogen genome sequence is publicly available and no genome-sequencing project has been initiated for any species of the genus erwinia, which includes several important plant pathogens. this paper describes a targeted sample sequencing approach to study the genome of erwinia carotovora subsp. atroseptica (eca), a major soft-rot pathogen of potato. a large insert dna (approx. 115 kb) library of eca ... | 2002 | 11988510 |
| temperature-dependent production of carotovoricin er and pectin lyase in phytopathogenic erwinia carotovora subsp. carotovora er. | the production of pectin lyase (pnl) and carotovoricin (ctv), as well as cell lysis in the plant-pathogenic bacterium erwinia carotovora subsp. carotovora er are induced by mitomycin c. here, pnl and ctv production and cell lysis were found to be temperature-dependent. the optimal temperature for pnl production was 30 degrees c. however, the optimal temperature for both ctv production and cell lysis was 23 degrees c, at which pnl production was reduced to 47% of the maximum. these data suggest t ... | 2002 | 11999425 |
| detection of bacterial infection of agave plants by laser-induced fluorescence. | greenhouse-grown plants of agave tequilana weber var. azul were inoculated with erwinia carotovora, the causal agent of stem soft rot. we investigated the laser-induced fluorescence (lif) of agave plants to determine whether lif can be used as a noninvasive sensing tool for pathological studies. the lif technique was also investigated as a means of detecting the effect of the polyamine biosynthesis inhibitor beta-hydroxyethylhydrazine as a bactericide against the pathogenic bacterium erwinia car ... | 2002 | 12009165 |
| identification of a quorum-sensing signal molecule in the facultative intracellular pathogen brucella melitensis. | brucella melitensis is a gram-negative alpha2-proteobacterium responsible for abortion in goats and for malta fever in humans. this facultative intracellular pathogen invades and survives within both professional and nonprofessional phagocytes. a dichloromethane extract of spent culture supernatant from b. melitensis induces bioluminescence in an escherichia coli acyl-homoserine lactone (acyl-hsl) biosensor strain based upon the activity of the lasr protein of pseudomonas aeruginosa. hplc fracti ... | 2002 | 12010991 |
| natural variability in the arabidopsis response to infection with erwinia carotovora subsp. carotovora. | the natural variation in the response of arabidopsis thaliana (l.) heynh. to erwinia carotovora subsp. carotovora has been studied in seven ecotypes and two mutants. the susceptibility of all the plant types was investigated by (i) macroscopic symptoms, (ii) fluorescence microscopy using green fluorescent protein (gfp) and (iii) bacterial growth in planta. although all the plants were susceptible to the bacterium, there was no correlation in the degree of infection as ascertained by the three me ... | 2002 | 12029469 |
| identification of two quorum-sensing systems in sinorhizobium meliloti. | sinorhizobium meliloti is a free-living soil bacterium which is capable of establishing a symbiotic relationship with the alfalfa plant (medicago sativa). this symbiosis involves a network of bacterium-host signaling, as well as the potential for bacterium-bacterium communication, such as quorum sensing. in this study, we characterized the production of n-acyl homoserine lactones (ahls) by two commonly used s. meliloti strains, ak631 and rm1021. we found that ak631 produces at least nine differe ... | 2002 | 12057940 |
| differential regulation of multiple proteins of escherichia coli and salmonella enterica serovar typhimurium by the transcriptional regulator slya. | slya is a transcriptional regulator of escherichia coli, salmonella enterica, and other bacteria belonging to the enterobacteriaceae: the slya protein has been shown to be involved in the virulence of s. enterica serovar typhimurium, but its role in e. coli is unclear. in this study, we employed the proteome technology to analyze the slya regulons of enteroinvasive e. coli (eiec) and salmonella serovar typhimurium. in both cases, comparative analysis of the two-dimensional protein maps of a wild ... | 2002 | 12057949 |
| interaction of ozone and negative air ions to control micro-organisms. | the aims of this study were to investigate the effect of ozone and/or negative air ions (nai) on the viability of bacteria. | 2002 | 12067383 |
| potentiation of developmentally regulated plant defense response by atwrky18, a pathogen-induced arabidopsis transcription factor. | atwrky18 is a pathogen- and salicylic acid-induced arabidopsis transcription factor containing the plant-specific wrky zinc finger dna-binding motif. in the present study, we have transformed arabidopsis plants with atwrky18 under control of the cauliflower mosaic virus 35s promoter. surprisingly, transgenic plants expressing high levels of atwrky18 were stunted in growth. when expressed at moderate levels, atwrky18 potentiated developmentally regulated defense responses in transgenic plants wit ... | 2002 | 12068113 |
| [isolation and genetic study of erwinia mutants devoid of common components of the phosphoenolpyruvate-dependent phosphotransferase system]. | mutants of bacteria belonging the genus erwinia (erwinia chrysanthemi and erwinia carotovora) with pleiotropic disturbances in the utilization of many substrates were obtained through chemical and transposon mutagenesis. genetic studies revealed that these mutants had defective ptsi or ptsh genes responsible for the synthesis of common components of the phosphoenolpyruvate-dependent phosphotransferase system, enzyme i and the hpr protein, respectively. the ptsi+ allele in both erwinia species wa ... | 2002 | 12068545 |
| cloning and relational analysis of 15 novel fungal endoglucanases from family 12 glycosyl hydrolase. | cellulases belong to the large family of glycosyl hydrolases (ghs) and are produced by a variety of bacteria and fungi. these extracellular enzymes act as endoglucanases (egs), cellobiohydrolases or beta-glucosidases. in this paper, we describe molecular screening for egs from the gh family 12. using three homologous sequence boxes deduced from five previously known members of the family, we analysed 22 cellulase-producing fungal strains obtained from a diverse area of the fungal kingdom. polyme ... | 2002 | 12073090 |
| secondary (gamma-proteobacteria) endosymbionts infect the primary (beta-proteobacteria) endosymbionts of mealybugs multiple times and coevolve with their hosts. | mealybugs (hemiptera, coccoidea, pseudococcidae) are plant sap-sucking insects that have within their body cavities specialized cells containing prokaryotic primary endosymbionts (p-endosymbionts). the p-endosymbionts have the unusual property of containing within their cytoplasm prokaryotic secondary endosymbionts (s-endosymbionts) [c. d. von dohlen, s. kohler, s. t. alsop, and w. r. mcmanus, nature (london) 412:433-436, 2001]. four-kilobase fragments containing 16s-23s ribosomal dna (rdna) wer ... | 2002 | 12088994 |
| altering plant-microbe interaction through artificially manipulating bacterial quorum sensing. | many bacteria regulate diverse physiological processes in concert with their population size. bacterial cell-to-cell communication utilizes small diffusible signal molecules, which the bacteria both produce and perceive. the bacteria couple gene expression to cell density by eliciting a response only when the signalling molecules reach a critical threshold (a point at which the population is said to be 'quorate'). the population as a whole is thus able to modify its behaviour as a single unit. a ... | 2002 | 12096736 |
| rsma and the quorum-sensing signal, n-[3-oxohexanoyl]-l-homoserine lactone, control the levels of rsmb rna in erwinia carotovora subsp. carotovora by affecting its stability. | rsma (for regulator of secondary metabolism), rsmc, and rsmb rna, the components of a posttranscriptional regulatory system, control extracellular protein production and pathogenicity in erwinia carotovora subsp. carotovora. rsma, an rna binding protein, acts as a negative regulator by promoting message decay. rsmb rna, on the other hand, acts as a positive regulator by neutralizing the effect of rsma. rsmc modulates the levels of rsma and rsmb rna by positively regulating rsma and negatively co ... | 2002 | 12107125 |
| diverse bacteria are pathogens of caenorhabditis elegans. | practically and ethically attractive as model systems, invertebrate organisms are increasingly recognized as relevant for the study of bacterial pathogenesis. we show here that the nematode caenorhabditis elegans is susceptible to a surprisingly broad range of bacteria and may constitute a useful model for the study of both pathogens and symbionts. | 2002 | 12117988 |
| the crystal structure of anthranilate phosphoribosyltransferase from the enterobacterium pectobacterium carotovorum. | the structure of anthranilate phosphoribosyltransferase from the enterobacterium pectobacterium carotovorum has been solved at 2.4 a in complex with mn(2+)-pyrophosphate, and at 1.9 a without ligands. the enzyme structure has a novel phosphoribosyltransferase (prt) fold and displays close homology to the structures of pyrimidine nucleoside phosphorylases. the enzyme is a homodimer with a monomer of 345 residues. each monomer consists of two subdomains, alpha and alpha/beta, which form a cleft co ... | 2002 | 12123839 |
| [defective lysogeny in erwinia carotovora]. | the electron microscopic study of several erwinia carotovora strains showed that the sos-induced cells of this pectolytic phytopathogenic bacterium produce particular phage parts (tails, heads, and baseplates) but do not assemble them into fully functional phage particles. e. carotovora cells produced several times greater amounts of phage tails in response to induction by mitomycin c than in response to induction by nalidixic acid. the tails were 128-192 nm in length and 13-21 nm in diameter. p ... | 2002 | 12138758 |
| identification, characterization, and regulation of a cluster of genes involved in carbapenem biosynthesis in photorhabdus luminescens. | the luminescent entomopathogenic bacterium photorhabdus luminescens produces several yet-uncharacterized broad-spectrum antibiotics. we report the identification and characterization of a cluster of eight genes (named cpma to cpmh) responsible for the production of a carbapenem-like antibiotic in strain tt01 of p. luminescens. the cpm cluster differs in several crucial aspects from other car operons. the level of cpm mrna peaks during exponential phase and is regulated by a rap/hor homolog ident ... | 2002 | 12147472 |
| genes encoding the n-acyl homoserine lactone-degrading enzyme are widespread in many subspecies of bacillus thuringiensis. | gram-negative bacteria can communicate with each other by n-acyl homoserine lactones (ahls), which are quorum-sensing autoinducers. recently, the aiia gene (encoding an enzyme catalyzing the degradation of ahl) has been cloned from bacillus sp. strain 240b1. during investigations in the course of the ongoing bacillus thuringiensis subsp. morrisoni genome project, an aiia homologue gene in the genome sequence was found. these results led to consideration of the possibility of the widespread exist ... | 2002 | 12147491 |
| lasr, a transcriptional activator of pseudomonas aeruginosa virulence genes, functions as a multimer. | the pseudomonas aeruginosa lasr protein functions in concert with n-3-oxo-dodecanoyl-l-homoserine lactone (3o-c(12)-hsl) to coordinate the expression of target genes, including many genes that encode virulence factors, with cell density. we used a lexa-based protein interaction assay to demonstrate that lasr forms multimers only when 3o-c(12)-hsl is present. a series of lasr molecules containing internal deletions or substitutions in single, conserved amino acid residues indicated that the n-ter ... | 2002 | 12169617 |
| inhibition of the plastidic atp/adp transporter protein primes potato tubers for augmented elicitation of defense responses and enhances their resistance against erwinia carotovora. | tubers of transgenic potato (solanum tuberosum) plants with decreased activity of the plastidic atp/adp transporter aatp1 display reduced levels of starch, modified tuber morphology, and altered concentrations of primary metabolites. here, we demonstrate that the spontaneous production of hydrogen peroxide, the endogenous content of salicylic acid, and the levels of mrnas of various defense-related genes are similar in tuber discs of wild-type and aatp1(st) antisense plants. however, upon challe ... | 2002 | 12177473 |
| constitutive expression of hrap gene in transgenic tobacco plant enhances resistance against virulent bacterial pathogens by induction of a hypersensitive response. | hypersensitive response-assisting protein (hrap) has been previously reported as an amphipathic plant protein isolated from sweet pepper that intensifies the harpin(pss)-mediated hypersensitive response (hr). the hrap gene has no appreciable similarity to any other known sequences, and its activity can be rapidly induced by incompatible pathogen infection. to assess the function of the hrap gene in plant disease resistance, the camv 35s promoter was used to express sweet pepper hrap in transgeni ... | 2002 | 12182333 |
| [method for studying horizontal transfer of plasmids in erwinia carotovora]. | a simple method to determine frequency characteristics of the horizontal transfer of antibiotic resistance by transconjugative plasmids of various incompatibility groups into erwinia carotovora strains has been developed. the proposed method for selection of e. carotovora transconjugates provides for the use of selective medium with pectin and corresponding antibiotic, which permits carrying out reliable counterselection of the donor (escherichia, salmonella). the proposed method helped to study ... | 2002 | 12190030 |
| regulatory circuitry of the csra/csrb and bara/uvry systems of escherichia coli. | the global regulator csra (carbon storage regulator) is an rna binding protein that coordinates central carbon metabolism, activates flagellum biosynthesis and motility, and represses biofilm formation in escherichia coli. csra activity is antagonized by the untranslated rna csrb, to which it binds and forms a globular ribonucleoprotein complex. csra indirectly activates csrb transcription, in an apparent autoregulatory mechanism. in the present study, we elucidate the intermediate regulatory ci ... | 2002 | 12193630 |
| the crystal structure of the quorum sensing protein trar bound to its autoinducer and target dna. | the quorum sensing system allows bacteria to sense their cell density and initiate an altered pattern of gene expression after a sufficient quorum of cells has accumulated. in agrobacterium tumefaciens, quorum sensing controls conjugal transfer of the tumour- inducing plasmid, responsible for plant crown gall disease. the core components of this system are the transcriptional regulator trar and its inducing ligand n-(3-oxo-octanoyl)-l-homoserine lactone. this complex binds dna and activates gene ... | 2002 | 12198141 |
| biodegradation of the polyketide toxin cercosporin. | cercosporin is a non-host-specific polyketide toxin produced by many species of plant pathogens belonging to the genus cercospora. this red-pigmented, light-activated toxin is an important pathogenicity determinant for cercospora species. in this study, we screened 244 bacterial isolates representing 12 different genera for the ability to degrade cercosporin. cercosporin degradation was determined by screening for the presence of cleared zones surrounding colonies on cercosporin-containing cultu ... | 2002 | 12200262 |
| the fibronectin type 3-like repeat from the clostridium thermocellum cellobiohydrolase cbha promotes hydrolysis of cellulose by modifying its surface. | fibronectin type 3 homology domains (fn3) as found in the cellobiohydrolase cbha of clostridium thermocellum are common among bacterial extracellular glycohydrolases. the function of these domains is not clear. cbha is modular and composed of an n-terminal family iv carbohydrate-binding domain (cbdiv), an immunoglobulin-like domain, a family 9 glycosyl hydrolase catalytic domain (gh9), two fn3-like domains (fn3(1,2)), a family iii carbohydrate-binding domain (cbdiii), and a dockerin domain. effi ... | 2002 | 12200278 |
| predicted structure and phyletic distribution of the rna-binding protein hfq. | hfq, a bacterial rna-binding protein, was recently shown to contain the sm1 motif, a characteristic of sm and lsm proteins that function in rna processing events in archaea and eukaryotes. in this report, comparative structural modeling was used to predict a three-dimensional structure of the hfq core sequence. the predicted structure aligns with most major features of the methanobacterium thermoautotrophicum lsm protein structure. conserved residues in hfq are positioned at the same structural ... | 2002 | 12202750 |
| whole-genome comparative analysis of three phytopathogenic xylella fastidiosa strains. | xylella fastidiosa (xf) causes wilt disease in plants and is responsible for major economic and crop losses globally. owing to the public importance of this phytopathogen we embarked on a comparative analysis of the complete genome of xf pv citrus and the partial genomes of two recently sequenced strains of this species: xf pv almond and xf pv oleander, which cause leaf scorch in almond and oleander plants, respectively. we report a reanalysis of the previously sequenced xf 9a5c (cvc, citrus) st ... | 2002 | 12205291 |
| signal transduction and regulatory mechanisms involved in control of the sigma(s) (rpos) subunit of rna polymerase. | the sigma(s) (rpos) subunit of rna polymerase is the master regulator of the general stress response in escherichia coli and related bacteria. while rapidly growing cells contain very little sigma(s), exposure to many different stress conditions results in rapid and strong sigma(s) induction. consequently, transcription of numerous sigma(s)-dependent genes is activated, many of which encode gene products with stress-protective functions. multiple signal integration in the control of the cellular ... | 2002 | 12208995 |
| n-acylhomoserine lactones undergo lactonolysis in a ph-, temperature-, and acyl chain length-dependent manner during growth of yersinia pseudotuberculosis and pseudomonas aeruginosa. | in gram-negative bacterial pathogens, such as pseudomonas aeruginosa and yersinia pseudotuberculosis, cell-to-cell communication via the n-acylhomoserine lactone (ahl) signal molecules is involved in the cell population density-dependent control of genes associated with virulence. this phenomenon, termed quorum sensing, relies upon the accumulation of ahls to a threshold concentration at which target structural genes are activated. by using biosensors capable of detecting a range of ahls we obse ... | 2002 | 12228292 |
| multidrug pump inhibitors uncover remarkable activity of plant antimicrobials. | plant antimicrobials are not used as systemic antibiotics at present. the main reason for this is their low level of activity, especially against gram-negative bacteria. the reported mic is often in the range of 100 to 1,000 micro g/ml, orders of magnitude higher than those of common broad-spectrum antibiotics from bacteria or fungi. major plant pathogens belong to the gram-negative bacteria, which makes the low level of activity of plant antimicrobials against this group of microorganisms puzzl ... | 2002 | 12234835 |
| regulation of erwinia carotovora hrpl(ecc) (sigma-l(ecc)), which encodes an extracytoplasmic function subfamily of sigma factor required for expression of the hrp regulon. | in erwinia carotovora subsp. carotovora (ecc) strain 71 (ecc71), hrpl(ecc), an alternate sigma factor of the extracytoplasmic function subfamily, plays a central role in the expression of the hrp (hypersensitive reaction and pathogenicity) regulon. we document here that sigma-54 (rpon) is required for full expression of hrpl(ecc) and that hrps, in conjunction with sigma-54, activates hrpl(ecc) transcription. we also made the novel observation that integration host factor is required for the acti ... | 2002 | 12236604 |
| salicylic acid interferes with tobacco mosaic virus replication via a novel salicylhydroxamic acid-sensitive mechanism. | salicylic acid (sa) induces resistance to all plant pathogens, including bacteria, fungi, and viruses, but the mechanism by which sa engenders resistance to viruses is not known. pretreatment of tobacco mosaic virus (tmv)-susceptible (nn genotype) tobacco tissue with sa reduced the levels of viral rnas and viral coat protein accumulating after inoculation with tmv. viral rnas were not affected equally, suggesting that sa treatment interferes with tmv replication. salicylhydroxamic acid (sham), a ... | 1997 | 12237364 |
| [in vitro self assembly of supermolecular structures after spontaneous disassembly of carotovoricins]. | the self-assembly of supramolecular structures (empty sheaths and polysheaths of the macromolecular erwinia carotovora bacteriocins) was studied by electron microscopy in the course of 1- to 2-year incubation of phage particles at 4 degrees c. this study showed that the empty sheaths and polysheaths of the bacteriocins of eight e. carotovora strains spontaneously assemble at the self-assembly centers (or crystallization centers), which have a diameter of 26-65 nm and contain a dense proteinaceou ... | 2002 | 12244715 |
| heca, a member of a class of adhesins produced by diverse pathogenic bacteria, contributes to the attachment, aggregation, epidermal cell killing, and virulence phenotypes of erwinia chrysanthemi ec16 on nicotiana clevelandii seedlings. | erwinia chrysanthemi is representative of a broad class of bacterial pathogens that are capable of inducing necrosis in plants. the e. chrysanthemi ec16 heca gene predicts a 3,850-aa member of the bordetella pertussis filamentous hemagglutinin family of adhesins. a hecatn7 mutant was reduced in virulence on nicotiana clevelandii seedlings after inoculation without wounding. epifluorescence and confocal laser-scanning microscopy observations of heca and wild-type cells expressing the green fluore ... | 2002 | 12271135 |
| inhibition of hydrolytic enzyme activities and plant pathogen growth by invertase inhibitors. | the invertase inhibitory protein isolated from cyphomandra betacea sendt and solanum tuberosum inhibited the invertase activity from different species, genera and even plant family. furthermore, proteinaceous inhibitors are not invertase specific; fungal, bacterial and higher plant enzymes including polygalacturonase, pectinase, pectin lyase, alpha-l-arabinofuranosidase and beta-glucosidase are also shown to be inhibited. both inhibitors exhibited an in vitro antibacterial action against phytopa ... | 2002 | 12365459 |
| in vitro efficacy of plant volatiles for inhibiting the growth of fruit and vegetable decay microorganisms. | the effects of acetaldehyde, benzaldehyde, cinnamaldehyde, ethanol, benzyl alcohol, nerolidol, 2-nonanone, beta-ionone, and ethyl formate vapors on the growth of rhizopus stolonifer, penicillium digitatum, colletotrichum musae, erwinia carotovora, and pseudomonas aeruginosa on agar medium were evaluated. the aldehydes were found to be the strongest growth inhibitors and the most lethal to the fungal spores and mycelia and bacterial cells. the average minimum inhibitory concentrations (mics) of a ... | 2002 | 12381119 |
| characterization of serracin p, a phage-tail-like bacteriocin, and its activity against erwinia amylovora, the fire blight pathogen. | serratia plymithicum j7 culture supernatant displayed activity against many pathogenic strains of erwinia amylovora, the causal agent of the most serious bacterial disease of apple and pear trees, fire blight, and against klebsiella pneumoniae, serratia liquefaciens, serratia marcescens, and pseudomonas fluorescens. this activity increased significantly upon induction with mitomycin c. a phage-tail-like bacteriocin, named serracin p, was purified from an induced culture supernatant of s. plymith ... | 2002 | 12406768 |
| the regulation of virulence in phytopathogenic erwinia species: quorum sensing, antibiotics and ecological considerations. | erwinia carotovora is a gram-negative bacterial phytopathogen that causes soft-rot disease and potato blackleg. the organism is environmentally widespread and exhibits an opportunistic plant pathogenesis. the ability to secrete multiple plant cell wall-degrading enzymes is a key virulence trait and exoenzyme production is responsive to multiple environmental and physiological cues. one important cue is the cell population density of the pathogen. cell density is monitored via an acylated homoser ... | 2002 | 12448721 |
| relatedness of chromosomal and plasmid dnas of erwinia pyrifoliae and erwinia amylovora. | the plant pathogen erwinia pyrifoliae has been classified as a separate species from erwinia amylovora based in part on differences in molecular properties. in this study, these and other molecular properties were examined for e. pyrifoliae and for additional strains of e. amylovora, including strains from brambles (rubus spp.). the nucleotide composition of the internal transcribed spacer (its) region was determined for six of the seven 16s-23s rrna operons detected in these species with a 16s ... | 2002 | 12450843 |
| coexistence of multiple proteobacterial endosymbionts in the gills of the wood-boring bivalve lyrodus pedicellatus (bivalvia: teredinidae). | wood-boring bivalves of the family teredinidae (commonly called shipworms) are known to harbor dense populations of gram-negative bacteria within specialized cells (bacteriocytes) in their gills. these symbionts are thought to provide enzymes, e.g., cellulase and dinitrogenase, which assist the host in utilizing wood as a primary food source. a cellulolytic, dinitrogen-fixing bacterium, teredinibacter turnerae, has been isolated from the gill tissues of numerous teredinid bivalves and has been p ... | 2002 | 12450854 |
| microbial biodiversity: approaches to experimental design and hypothesis testing in primary scientific literature from 1975 to 1999. | research interest in microbial biodiversity over the past 25 years has increased markedly as microbiologists have become interested in the significance of biodiversity for ecological processes and as the industrial, medical, and agricultural applications of this diversity have evolved. one major challenge for studies of microbial habitats is how to account for the diversity of extremely large and heterogeneous populations with samples that represent only a very small fraction of these population ... | 2002 | 12456784 |
| spatio-temporal expression of patatin-like lipid acyl hydrolases and accumulation of jasmonates in elicitor-treated tobacco leaves are not affected by endogenous levels of salicylic acid. | we have previously isolated three tobacco genes (ntpat) encoding patatin-like proteins, getting rapidly induced during the hypersensitive response (hr) to tobacco mosaic virus, in advance to jasmonate accumulation. ntpat enzymes are lipid acyl hydrolases that display high phospholipase a2 (pla2) activity and may mobilize fatty acid precursors of oxylipins. here, we performed a detailed study of ntpat gene regulation under various biotic and abiotic stresses. pla2 activity was poorly induced in r ... | 2002 | 12472690 |
| role of rsma in the regulation of swarming motility and virulence factor expression in proteus mirabilis. | swarming by proteus mirabilis involves differentiation of typical short vegetative rods into filamentous hyper-flagellated swarm cells that undergo cycles of rapid and co-ordinated population migration across surfaces and exhibit high levels of virulence gene expression. rsma (repressor of secondary metabolites) and csra, its homologue in escherichia coli, control many phenotypic traits, such as motility and pathogenesis in erwinia species, glycogen biosynthesis, cell size and biofilm formation ... | 2003 | 12488561 |
| oxyr acts as a repressor of catalase expression in neisseria gonorrhoeae. | it has been reported that neisseria gonorrhoeae possesses a very high level of catalase activity, but the regulation of catalase expression has not been investigated extensively. in escherichia coli and salmonella enterica serovar typhimurium, it has been demonstrated that oxyr is a positive regulator of hydrogen peroxide-inducible genes, including the gene encoding catalase. the oxyr gene from n. gonorrhoeae was cloned and used to complement an e. coli oxyr mutant, confirming its identity and f ... | 2003 | 12496210 |
| phylogenetical relationship based on groe genes among phenotypically related enterobacter, pantoea, klebsiella, serratia and erwinia species. | in an attempt to define the phylogenetical relationship among 17 phenotypically related species of genera enterobacter, pantoea, serratia, klebsiella and erwinia, we determined almost all of their groe operon sequences using the polymerase chain reaction direct sequencing method. the number of nucleotide substitutions per site was 0.12+/-0.030. the value was 3.6-fold higher than that of 16s rdna. as a result, we were successful in constructing molecular phylogenetic trees which had a finer resol ... | 1997 | 12501307 |
| ethylene response factor1 integrates signals from ethylene and jasmonate pathways in plant defense. | cross-talk between ethylene and jasmonate signaling pathways determines the activation of a set of defense responses against pathogens and herbivores. however, the molecular mechanisms that underlie this cross-talk are poorly understood. here, we show that ethylene and jasmonate pathways converge in the transcriptional activation of ethylene response factor1 (erf1), which encodes a transcription factor that regulates the expression of pathogen response genes that prevent disease progression. the ... | 2003 | 12509529 |
| celi, a noncellulosomal family 9 enzyme from clostridium thermocellum, is a processive endoglucanase that degrades crystalline cellulose. | the family 9 cellulase gene celi of clostridium thermocellum, was previously cloned, expressed, and characterized (g. p. hazlewood, k. davidson, j. i. laurie, n. s. huskisson, and h. j. gilbert, j. gen. microbiol. 139:307-316, 1993). we have recloned and sequenced the entire celi gene and found that the published sequence contained a 53-bp deletion that generated a frameshift mutation, resulting in a truncated and modified c-terminal segment of the protein. the enzymatic properties of the wild-t ... | 2003 | 12511483 |
| functional and mutational analysis of conjugative transfer region 2 (tra2) from the inchi1 plasmid r27. | the transfer 2 region (tra2) of the conjugative plasmid drr27 (derepressed r27) was analyzed by psi-blast, insertional mutagenesis, genetic complementation, and an h-pilus assay. tra2 contains 11 mating-pair formation (mpf) genes that are essential for conjugative transfer, 9 of which are essential for h-pilus production (trha, -l, -e, -k, -b, -v, -c, -p, and -w). trhk has similarity to secretin proteins, suggesting a mechanism by which dna could traverse the outer membrane of donors. the remain ... | 2003 | 12511505 |
| a colonization factor (production of lateral flagella) of mesophilic aeromonas spp. is inactive in aeromonas salmonicida strains. | the nine laf (lateral flagellum) genes of mesophilic aeromonads are in the aeromonas salmonicida genome. the laf genes are functional, except for lafa (flagellin gene), which was inactivated by transposase 8 (is3 family). a pathogenic characteristic of mesophilic aeromonads (lateral flagella) is abolished in this specialized pathogen with a narrow host range. | 2003 | 12514057 |
| nitric oxide contributes to induction of innate immune responses to gram-negative bacteria in drosophila. | studies in mammals uncovered important signaling roles of nitric oxide (no), and contributions to innate immunity. suggestions of conservation led us to explore the involvement of no in drosophila innate immunity. inhibition of nitric oxide synthase (nos) increased larval sensitivity to gram-negative bacterial infection, and abrogated induction of the antimicrobial peptide diptericin. nos was up-regulated after infection. antimicrobial peptide reporters revealed that no triggered an immune respo ... | 2003 | 12514104 |
| 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 |
| modulation of cyp79 genes and glucosinolate profiles in arabidopsis by defense signaling pathways. | glucosinolates are natural plant products that function in the defense toward herbivores and pathogens. plant defense is regulated by multiple signal transduction pathways in which salicylic acid (sa), jasmonic acid, and ethylene function as signaling molecules. glucosinolate content was analyzed in arabidopsis wild-type plants in response to single or combinatorial treatments with methyljasmonate (meja), 2,6-dichloro-isonicotinic acid, ethylene, and 2,4-dichloro-phenoxyacetic acid, or by woundi ... | 2003 | 12529537 |
| bacterial autoinduction: looking outside the cell for new metabolic engineering targets. | recent evidence has demonstrated that cell-to-cell signaling is a fundamental activity carried out by numerous microorganisms. a number of specialized processes are reported to be regulated by density-dependent signaling molecules including antibiotic production, bioluminescence, biofilm formation, genetic competence, sporulation, swarming motility and virulence. however, a more centralized role for quorum sensing is emerging where quorum signaling pathways overlap with stress and starvation cir ... | 2002 | 12537600 |
| [type iii secretion system in se9r can recognize and secret harpin in erwinia amylovora]. | bacterial pathogens of both animals and plants use type iii secretion machines to secret virulence proteins. the signal that leads to tye type iii secretion is encoded as stem loop structure in the messenger rna. harpin, produced by erwinia anylovora is secreted via type iii secretion. erwinia carotovora se9r and erwinia amylovora belong to the same genus and they use type iii secretion machines to secret virulence proteins. we used pcr to amplify hrpn from pcpp430 which harbors hrpn gene cluste ... | 2002 | 12557554 |
| enhancement of population size of a biological control agent and efficacy in control of bacterial speck of tomato through salicylate and ammonium sulfate amendments. | sodium salicylate and ammonium sulfate were applied to leaf surfaces along with suspensions of the biological control agents pseudomonas syringae cit7(pnah7), which catabolizes salicylate, and cit7, which does not catabolize salicylate, to determine whether enhanced biological control of bacterial speck of tomato could be achieved. foliar amendment with salicylate alone significantly enhanced the population size and the efficacy of cit7(pnah7), but not of cit7, on tomato leaves. application of a ... | 2003 | 12571060 |
| vibrio harveyi quorum sensing: a coincidence detector for two autoinducers controls gene expression. | in a process called quorum sensing, bacteria communicate with one another by exchanging chemical signals called autoinducers. in the bioluminescent marine bacterium vibrio harveyi, two different auto inducers (ai-1 and ai-2) regulate light emission. detection of and response to the v.harveyi autoinducers are accomplished through two two-component sensory relay systems: ai-1 is detected by the sensor luxn and ai-2 by luxpq. here we further define the v.harveyi quorum-sensing regulon by identifyin ... | 2003 | 12574123 |
| rhamnogalacturonate lyase rhie is secreted by the out system in erwinia chrysanthemi. | supernatants of rhamnose-induced erwinia chrysanthemi strain 3937 cultures contain a principal secreted protein named rhie. a rhie mutant has been found among a set of rhamnose-induced mudi1681 lacz fusions. rhie is a 62-kda protein that has rhamnogalacturonate lyase activity on rhamnogalacturonan i (rg-i). it does not require a divalent cation for its activity and has an optimal ph of 6.0. rhie expression is strongly induced in the presence of rhamnose but is also regulated by pect and crp, two ... | 2003 | 12591882 |
| a single gene that promotes interaction of a phytopathogenic bacterium with its insect vector, drosophila melanogaster. | insects are major vectors of plant and animal disease, and bacterial phytopathogens are often disseminated by flies. we have previously reported that some isolates of the phytopathogenic bacterial species erwinia carotovora infect drosophila and activate an immune response. using a genetic screen, we have now identified two genes that are required by e. carotovora to infect drosophila. one of these genes has a regulatory role whereas the other, evf, confers an infectious phenotype: its transfer ... | 2003 | 12612613 |
| mutational analysis of the residue at position 48 in the salmonella enterica serovar typhimurium phoq sensor kinase. | the phop/phoq two-component regulatory system of salmonella enterica serovar typhimurium plays an essential role in controlling virulence by mediating the adaptation to mg(2+) depletion. the pho-24 allele of phoq harbors a single amino acid substitution (t48i) in the periplasmic domain of the phoq histidine kinase sensor. this mutation has been shown to increase net phosphorylation of the phop response regulator. we analyzed the effect on signaling by phop/phoq of various amino acid substitution ... | 2003 | 12618457 |
| quorum-sensing system and stationary-phase sigma factor (rpos) of the onion pathogen burkholderia cepacia genomovar i type strain, atcc 25416. | bacterial strains belonging to burkholderia cepacia can be human opportunistic pathogens, plant pathogens, and plant growth promoting and have remarkable catabolic activity. b. cepacia consists of several genomovars comprising what is now known as the b. cepacia complex. here we report the quorum-sensing system of a genomovar i onion rot type strain atcc 25416. quorum sensing is a cell-density-dependent regulatory response which involves the production of n-acyl homoserine lactone (hsl) signal m ... | 2003 | 12620866 |
| two families of mechanosensitive channel proteins. | mechanosensitive (ms) channels that provide protection against hypoosmotic shock are found in the membranes of organisms from the three domains of life: bacteria, archaea, and eucarya. two families of ubiquitous ms channels are recognized, and these have been designated the mscl and mscs families. a high-resolution x-ray crystallographic structure is available for a member of the mscl family, and extensive molecular genetic, biophysical, and biochemical studies conducted in many laboratories hav ... | 2003 | 12626684 |
| crystal structure of enterococcus faecalis slya-like transcriptional factor. | the crystal structure of a slya transcriptional regulator at 1.6 a resolution is presented, and structural relationships between members of the marr/slya family are discussed. the slya family, which includes slya, rap, hor, and rova proteins, is widely distributed in bacterial and archaeal genomes. current evidence suggests that slya-like factors act as repressors, activators, and modulators of gene transcription. these proteins have been shown to up-regulate the expression of molecular chaperon ... | 2003 | 12649270 |
| erwinia carotovora subsp. carotovora and erwinia-derived elicitors hrpn and peha trigger distinct but interacting defense responses and cell death in arabidopsis. | we have used an hrp-positive strain of the soft rot pathogen erwinia carotovora subsp. carotovora to elucidate plant responses to this bacterial necrotroph. purified virulence determinants, harpin (hrpn) and polygalacturonase (peha), were used as tools to facilitate this analysis. we show that hrpn elicits lesion formation in arabidopsis and tobacco and triggers systemic resistance in arabidopsis. establishment of resistance is accompanied by the expression of salicylic acid (sa)-dependent, but ... | 2003 | 12650449 |
| comparative study of regulatory mechanisms for pectinase production by erwinia carotovora subsp. carotovora and erwinia chrysanthemi. | the production of pectinase, the major virulence determinant of soft-rot erwinia species, is controlled by many regulatory factors. we focused on the major regulatory proteins, kdgr, crp, pir, and pecs, characterized mainly in e. chrysanthemi, and tested for their presence and function in the control of pectate lyase (pel) and polygalacturonase (peh) production in e. carotovora subsp. carotovora. homologues of kdgr and crp but not of pir and pecs were detected by southern blot analyses in e. car ... | 2003 | 12650454 |
| novel virulence-associated type ii secretion system unique to high-pathogenicity yersinia enterocolitica. | yersinia enterocolitica strains comprise an important group of bacterial enteropathogens that cause a broad range of gastrointestinal syndromes. three groups are distinguishable within this bacterial species, namely, the nonpathogenic group (biotype 1a strains), the low-pathogenicity, non-mouse-lethal group (biotypes 2 to 5), and the high-pathogenicity, mouse-lethal group (biotype 1b). to date, the presence of the high-pathogenicity island (hpi), a chromosomal locus that encodes the yersiniabact ... | 2003 | 12654803 |
| 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 |
| elevation of three subspecies of pectobacterium carotovorum to species level: pectobacterium atrosepticum sp. nov., pectobacterium betavasculorum sp. nov. and pectobacterium wasabiae sp. nov. | a collection of 42 strains belonging to the five subspecies of pectobacterium carotovorum (subspecies atrosepticum, betavasculorum, carotovorum, odoriferum and wasabiae) and 11 reference and type strains of biovars of pectobacterium chrysanthemi, pectobacterium cacticidum and brenneria paradisiaca were studied by dna-dna hybridization, numerical taxonomy of 120 phenotypic characteristics, serology and new phylogenetic analysis of previously reported sequences from a database of aligned 16s rdna ... | 2003 | 12710602 |
| sweet pepper ferredoxin-like protein ( pflp) gene as a novel selection marker for orchid transformation. | a novel method for selection of transgenic plants utilizing the sweet pepper ( capsicum annuum l.) ferredoxin-like protein ( pflp) gene as selection marker and erwinia carotovora as the selection agent has been developed. an expression vector containing a pflp cdna driven by a cauliflower mosaic virus 35s promoter was successfully transformed into protocorm-like bodies of oncidium orchid by agrobacterium tumefaciens and particle bombardment, respectively. erwinia carotovora was used as a selecti ... | 2003 | 12721849 |
| enhanced resistance to phytophthora infestans and alternaria solani in leaves and tubers, respectively, of potato plants with decreased activity of the plastidic atp/adp transporter. | recently, it has been reported that tubers of transgenic potato ( solanum tuberosum l.) plants with decreased activity of the plastidic atp/adp transporter (aatp1) contain less starch, despite having an increased glucose level [p. geigenberger et al. (2001) plant physiol 125:1667-1678]. the metabolic alterations correlated with enhanced resistance to the bacterium erwinia carotovora. here it is shown that transgenic potato tubers, possessing less starch yet increased glucose levels due to the ex ... | 2003 | 12721851 |
| paex, a second pectin acetylesterase of erwinia chrysanthemi 3937. | erwinia chrysanthemi causes soft-rot diseases of various plants by enzymatic degradation of the pectin in plant cell walls. pectin is a complex polysaccharide. the main chain is constituted of galacturonate residues, and some of them are modified by methyl and/or acetyl esterification. esterases are necessary to remove these modifications and, thus, to facilitate the further degradation of the polysaccharidic chain. in addition to paey, the first pectin acetylesterase identified in the e. chrysa ... | 2003 | 12730169 |
| 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 |
| peh production, flagellum synthesis, and virulence reduced in erwinia carotovora subsp. carotovora by mutation in a homologue of cytr. | erwinia carotovora subsp. carotovora is a causal agent of soft-rot diseases in a wide variety of plants. here, we have isolated a new regulatory factor involved in the virulence of e. carotovora subsp. carotovora by in vivo insertional mutagenesis using a transposon tn5. the gene was homologous to cytr encoding a transcriptional repressor of nucleoside uptake and catabolism genes in escherichia coli, salmonella typhimurium, and vibrio cholerae. phenotypic characterization of a nonpolar deletion ... | 2003 | 12744509 |
| [the study of erwinia carotovora bacteriocins in the nalidixic acid resistant erwinia carotovora]. | a novel approach is proposed for the study of the macromolecular bacteriocins of erwinia carotovora (mctvs). the approach lies in that the bacteriocinogeny of pectolytic erwinia is studied using a lawn of a bacterial mutant resistant to nalidixic acid, an inducer of mctvs. the high efficiency of this approach was demonstrated by studying carotovoricins in 104 different e. carotovora strains, 88% of which bear mctvs, distinguished by the morphology of zones of induced lysis on a lawn of susceptib ... | 2003 | 12751244 |
| mutation of luxs of streptococcus pneumoniae affects virulence in a mouse model. | the luxs protein is required for the biosynthesis of the type 2 autoinducer (ai-2), which is involved in quorum sensing in a wide range of bacterial species. we have determined the effects of a defined luxs mutation on the virulence of streptococcus pneumoniae. although the luxs mutant displayed reduced virulence relative to its wild-type parent, the type 2 strain d39, it was by no means avirulent in a mouse model. after intranasal administration, the luxs mutant was able to colonize the nasopha ... | 2003 | 12761100 |
| ahld, an n-acylhomoserine lactonase in arthrobacter sp., and predicted homologues in other bacteria. | quorum sensing is a signalling mechanism that controls diverse biological functions, including virulence, via n-acylhomoserine lactone (ahl) signal molecules in gram-negative bacteria. with the aim of isolating strains or enzymes capable of blocking quorum sensing by inactivating ahl, bacteria were screened for ahl degradation by their ability to utilize n-3-oxohexanoyl-l-homoserine lactone (ohhl) as the sole carbon source. among four isolates, strain ibn110, identified as arthrobacter sp., was ... | 2003 | 12777494 |
| the sweet pepper ferredoxin-like protein (pflp) conferred resistance against soft rot disease in oncidium orchid. | genetic engineering to date has not been used to introduce disease resistance genes into the orchid gene pool. the ferredoxin-like protein gene originally isolated from sweet pepper is thought to function as a natural defense against infection due to its antimicrobial properties. hence it was reasoned that introduction of this gene might produce oncidium plants resistant to erwinia carotovora, the causal agent for the soft rot disease. an expression vector containing sweet pepper ferredoxin-like ... | 2003 | 12779121 |
| inhibition and alternate substrate studies on the mechanism of carbapenam synthetase from erwinia carotovora. | the erwinia carotorova cara, carb, and carc gene products are essential for the biosynthesis of (5r)-carbapen-2-em-3-carboxylic acid, the simplest carbapenem beta-lactam antibiotic. cara (hereafter named carbapenam synthetase) has been proposed to catalyze formation of (3s,5s)-carbapenam-3-carboxylic acid from (2s,5s)-5-carboxymethyl proline based on characterization of the products of fermentation experiments in escherichia coli cells transformed with pet24a/carb and pet24a/carab, and on sequen ... | 2003 | 12820893 |
| a novel potato defence-related alcohol:nadp+ oxidoreductase induced in response to erwinia carotovora. | identification of solanum tuberosum genes responsive to culture filtrates (cf) from erwinia carotovora subsp. carotovora led to the isolation of a full-length cdna with high sequence similarity to several alcohol dehydrogenases. accumulation of transcripts corresponding to this defence-related alcohol dehydrogenase (drd-1) was rapidly induced in cf-treated and wounded plants. the gene was also responsive to molecules involved in defence signalling such as salicylic acid, methyl jasmonate and eth ... | 2003 | 12825698 |
| the erwinia chrysanthemi phop-phoq operon plays an important role in growth at low ph, virulence and bacterial survival in plant tissue. | we have studied the role of acidic ph as a barrier for the colonization of the plant apoplast by erwinia chrysanthemi. a minitransposon containing a promoterless reporter gene, gus, was used for random mutagenesis of the bacterial genome. an acid-sensitive mutant, named bt119, was isolated and had the following differential features with respect to the wild-type strain: (i) inability to grow at ph </= 5.5; (ii) decreased survival at acid ph and in plant tissues; (iii) increased susceptibility to ... | 2003 | 12828634 |
| identification of a new ribosomal protection type of tetracycline resistance gene, tet(36), from swine manure pits. | previously, only one ribosome protection type of a tetracycline resistance gene, tetq, had been identified in bacteroides spp. during an investigation of anaerobic bacteria present in swine feces and manure storage pits, a tetracycline-resistant bacteroides strain was isolated. subsequent analysis showed that this new bacteroides strain, bacteroides sp. strain 139, did not contain tetq but contained a previously unidentified tetracycline resistance gene. sequence analysis showed that the tetracy ... | 2003 | 12839793 |
| detection and diversity assessment of xylella fastidiosa in field-collected plant and insect samples by using 16s rrna and gyrb sequences. | the causal agent of diseases in many economically important plants is attributed to the xylem-limited bacterium xylella fastidiosa. the detection of this plant pathogen has been hampered due to its difficult isolation and slow growth on plates. nearly complete nucleotide sequences of the 16s rrna gene and partial sequences of the gyrb gene were determined for 18 strains of x. fastidiosa isolated from different plant hosts. a phylogenetic analysis, based on gyrb, grouped strains in three clusters ... | 2003 | 12839807 |
| sequence of the escherichia coli o121 o-antigen gene cluster and detection of enterohemorrhagic e. coli o121 by pcr amplification of the wzx and wzy genes. | the dna sequence of the 15,155-bp o-antigen gene cluster of escherichia coli o121 was determined, and 14 open reading frames were identified (all had the same transcriptional direction). analyses of results indicated that the wzx (o-antigen flippase) and wzy (o-antigen polymerase) genes were e. coli o121 specific, so regions in these two genes were chosen for development of pcr assays. the pcr assays using dna from 99 e. coli o121 strains, strains representative of non-o121 e. coli serogroups, a ... | 2003 | 12843098 |
| sm-like proteins in eubacteria: the crystal structure of the hfq protein from escherichia coli. | the hfq protein was discovered in escherichia coli in the early seventies as a host factor for the qbeta phage rna replication. during the last decade, it was shown to be involved in many rna processing events and remote sequence homology indicated a link to spliceosomal sm proteins. we report the crystal structure of the e.coli hfq protein showing that its monomer displays a characteristic sm-fold and forms a homo-hexamer, in agreement with former biochemical data. overall, the structure of the ... | 2003 | 12853626 |
| [the bactericidal activity of lectins from nitrogen-fixing bacilli]. | lectins i and ii isolated from the nitrogen-fixing soil bacterium paenibacillus polymyxa 1460 were found to be able to suppress the growth of rhizobium leguminosarum 252 and bacillus subtilis 36 at nearly all the concentrations tested (from 1 to 10 micrograms/ml). lectin i was also inhibitory to azospirillum brasilense 245 and erwinia carotovora subsp. citrulis 603, while lectin ii exerted bactericidal activity against xanthomonas campestris b-610 and b-611 and a. brasilense 245. the bacillar le ... | 2003 | 12901008 |
| the ti plasmid of agrobacterium tumefaciens harbors an attm-paralogous gene, aiib, also encoding n-acyl homoserine lactonase activity. | the agrobacterium tumefaciens c58 genome contains three putative n-acyl homoserine lactone (acyl-hsl) hydrolases, which are closely related to the lactonase aiia of bacillus. when expressed in escherichia coli, two of the putative acyl-hsl hydrolases, attm and aiib, conferred the ability to degrade acyl-hsls on the host. in erwinia strain 6276, the lactonases reduced the endogenous acyl-hsl level and the bacterial virulence in planta. | 2003 | 12902298 |
| novel bacteria degrading n-acylhomoserine lactones and their use as quenchers of quorum-sensing-regulated functions of plant-pathogenic bacteria. | bacteria degrading the quorum-sensing (qs) signal molecule n-hexanoylhomoserine lactone were isolated from a tobacco rhizosphere. twenty-five isolates degrading this homoserine lactone fell into six groups according to their genomic rep-pcr and rrs pcr-rflp profiles. representative strains from each group were identified as members of the genera pseudomonas, comamonas, variovorax and rhodococcus: all these isolates degraded n-acylhomoserine lactones other than the hexanoic acid derivative, albei ... | 2003 | 12904538 |