| host specificity of mollicutes oric plasmids: functional analysis of replication origin. | recently, artificial oric plasmids containing the chromosomal dnaa gene and surrounding dnaa box sequences were obtained for the mollicutes spiroplasma citri and mycoplasma pulmonis. in order to study the specificity of these plasmids among mollicutes, a set of similar oric plasmids was developed for three mycoplasmas belonging to the mycoides cluster, mycoplasma mycoides subsp. mycoides lc (mmmlc), m.mycoides subsp. mycoides sc (mmmsc) and mycoplasma capricolum subsp. capricolum. mycoplasmas fr ... | 2003 | 14602921 |
| use of o-antigen gene cluster-specific pcrs for the identification and o-genotyping of yersinia pseudotuberculosis and yersinia pestis. | yersinia pestis is a very recently evolved clone of yersinia pseudotuberculosis serotype o:1b. this close relationship causes potential difficulties in dna-based diagnostic methods. analysis of the o-antigen gene clusters in these two organisms identified two regions that were used to specifically identify y. pestis-y. pseudotuberculosis as a group or y. pestis alone. both pcr assays were found to be 100% specific when tested on a large collection of yersinia species and other enterobacteriaceae ... | 2003 | 14605146 |
| the pmra-pmrb two-component system responding to acidic ph and iron controls virulence in the plant pathogen erwinia carotovora ssp. carotovora. | efficient response to environmental cues is crucial to successful infection by plant-pathogenic bacteria such as erwinia carotovora ssp. carotovora. the expression of the main virulence genes of this pathogen, encoding extracellular enzymes that degrade the plant-cell wall, is subject to complex regulatory machinery where two-component systems play an important role. in this paper, we describe for the first time the involvement of the pmra-pmrb two-component system in regulation of virulence in ... | 2003 | 14617142 |
| the quorum sensing negative regulators esar and expr(ecc), homologues within the luxr family, retain the ability to function as activators of transcription. | most luxr homologues function as activators of transcription during the process of quorum sensing, but a few, including esar and expr(ecc), negatively impact gene expression. the luxr-activated luxi promoter and luxr binding site, the lux box, were used in artificial contexts to assess the potential for transcriptional activation and dna binding by esar and expr(ecc). although the acyl-homoserine lactone responsiveness of both proteins is the opposite of that shown by most luxr family members, e ... | 2003 | 14617666 |
| isolation of enterobacter sakazakii from midgut of stomoxys calcitrans. | | 2003 | 14626227 |
| regulation of lysine biosynthesis and transport genes in bacteria: yet another rna riboswitch? | comparative analysis of genes, operons and regulatory elements was applied to the lysine biosynthetic pathway in available bacterial genomes. we report identification of a lysine-specific rna element, named the lys element, in the regulatory regions of bacterial genes involved in biosynthesis and transport of lysine. similarly to the previously described rna regulatory elements for three vitamins (riboflavin, thiamin and cobalamin), purine and methionine regulons, this regulatory rna structure i ... | 2003 | 14627808 |
| functional domains of the rhlr transcriptional regulator of pseudomonas aeruginosa. | the rhlr transcriptional regulator of pseudomonas aeruginosa, along with its cognate autoinducer, n-butyryl homoserine lactone (c(4)-hsl), regulates gene expression in response to cell density. with an escherichia coli lexa-based protein interaction system, we demonstrated that rhlr multimerized and that the degree of multimerization was dependent on the c(4)-hsl concentration. studies with an e. coli lasb::lacz lysogen demonstrated that rhlr multimerization was necessary for it to function as a ... | 2003 | 14645272 |
| gaca regulates symbiotic colonization traits of vibrio fischeri and facilitates a beneficial association with an animal host. | the gacs/gaca two-component system regulates the expression of bacterial traits during host association. although the importance of gacs/gaca as a regulator of virulence is well established, its role in benign associations is not clear, as mutations in either the gacs or gaca gene have little impact on the success of colonization in nonpathogenic associations studied thus far. using as a model the symbiotic association of the bioluminescent marine bacterium vibrio fischeri with its animal host, ... | 2003 | 14645281 |
| pathways leading from bara/sira to motility and virulence gene expression in salmonella. | the bara and sira genes of salmonella enterica serovar typhimurium encode a two-component sensor kinase and a response regulator, respectively. this system increases the expression of virulence genes and decreases the expression of motility genes. in this study, we examined the pathways by which sira affects these genes. we found that the master regulator of flagellar genes, flhdc, had a positive regulatory effect on the primary regulator of intestinal virulence determinants, hila, but that hila ... | 2003 | 14645287 |
| oxidative burst elicited by bacillus mycoides isolate bac j, a biological control agent, occurs independently of hypersensitive cell death in sugar beet. | response of sugar beet cultivars c40 and ush11 to syringe infiltration of live and dead bacillus mycoides isolate bac j, a biological control agent, and virulent and avirulent isolates of erwinia carotovora pv. betavasculorum was measured by monitoring systemic acquired resistance control of cercospora beticola, specific activity of chitinase and beta-glucanase, the oxidative burst, and hypersensitive cell death at the infiltration site. priming sugar beet with b. mycoides bac j (1 x 10(8) cells ... | 2003 | 14651348 |
| quorum sensing in nitrogen-fixing rhizobia. | members of the rhizobia are distinguished for their ability to establish a nitrogen-fixing symbiosis with leguminous plants. while many details of this relationship remain a mystery, much effort has gone into elucidating the mechanisms governing bacterium-host recognition and the events leading to symbiosis. several signal molecules, including plant-produced flavonoids and bacterially produced nodulation factors and exopolysaccharides, are known to function in the molecular conversation between ... | 2003 | 14665677 |
| npdr, a repressor involved in 2,4,6-trinitrophenol degradation in rhodococcus opacus hl pm-1. | rhodococcus opacus hl pm-1 utilizes 2,4,6-trinitrophenol (picric acid) as a sole nitrogen source. the initial attack on picric acid occurs through two hydrogenation reactions. hydride transferase ii (encoded by npdi) and hydride transferase i (encoded by npdc) are responsible for the hydride transfers. database searches with the npd genes have indicated the presence of a putative transcriptional regulator, npdr. here, the npdr gene was expressed in escherichia coli, and the protein was purified ... | 2004 | 14679229 |
| growth phase-dependent regulation and stringent control of fis are conserved processes in enteric bacteria and involve a single promoter (fis p) in escherichia coli. | the intracellular concentration of the escherichia coli factor for inversion stimulation (fis), a global regulator of transcription and a facilitator of certain site-specific dna recombination events, varies substantially in response to changes in the nutritional environment and growth phase. under conditions of nutritional upshift, fis is transiently expressed at very high levels, whereas under induced starvation conditions, fis is repressed by stringent control. we show that both of these regu ... | 2004 | 14679232 |
| legionella pneumophila type ii protein secretion promotes virulence in the a/j mouse model of legionnaires' disease pneumonia. | legionella pneumophila, the gram-negative agent of legionnaires' disease, possesses type iv pili and a type ii protein secretion (lsp) system, both of which are dependent upon the pild prepilin peptidase. by analyzing multiple pild mutants and various types of lsp mutants as well as performing trans-complementation of these mutants, we have confirmed that pild and type ii secretion genes are required for l. pneumophila infection of both amoebae and human macrophages. based upon a complete analys ... | 2004 | 14688110 |
| plant er genes that encode photorespiratory enzymes confer resistance against disease. | downy mildew caused by the oomycete pathogen pseudoperonospora cubensis is a devastating foliar disease of cucurbits worldwide. we previously demonstrated that the wild melon line pi 124111f (pi) is highly resistant to all pathotypes of p. cubensis. that resistance was controlled genetically by two partially dominant, complementary loci. here, we show that unlike other plant disease resistance genes, which confer an ability to resist infection by pathogens expressing corresponding avirulence gen ... | 2004 | 14688292 |
| complete sequence and evolutionary genomic analysis of the pseudomonas aeruginosa transposable bacteriophage d3112. | bacteriophage d3112 represents one of two distinct groups of transposable phage found in the clinically relevant, opportunistic pathogen pseudomonas aeruginosa. to further our understanding of transposable phage in p. aeruginosa, we have sequenced the complete genome of d3112. the genome is 37,611 bp, with an overall g+c content of 65%. we have identified 53 potential open reading frames, including three genes (the c repressor gene and early genes a and b) that have been previously characterized ... | 2004 | 14702309 |
| an evolutionary hot spot: the pngr234b replicon of rhizobium sp. strain ngr234. | rhizobium sp. strain ngr234 has an exceptionally broad host range and is able to nodulate more than 112 genera of legumes. since the overall organization of the ngr234 genome is strikingly similar to that of the narrow-host-range symbiont rhizobium meliloti strain 1021 (also known as sinorhizobium meliloti), the obvious question is why are the spectra of hosts so different? study of the early symbiotic genes of both bacteria (carried by the syma plasmids) did not provide obvious answers. yet, bo ... | 2004 | 14702322 |
| bacterial expression of a human monoclonal antibody-alkaline phosphatase conjugate specific for entamoeba histolytica. | we previously produced human monoclonal antibody fab fragments specific to entamoeba histolytica in escherichia coli. in order to use these fab fragments for diagnostic purposes, an expression vector to produce a fusion protein of fab and alkaline phosphatase (phoa) in e. coli was designed and constructed. the e. coli phoa gene was fused to the 3' terminus of the gene encoding the heavy-chain fd region. the kappa and fd genes from a previously prepared antibody clone, cp33, which is specific for ... | 2004 | 14715571 |
| parasite-specific immune response in adult drosophila melanogaster: a genomic study. | insects of the order diptera are vectors for parasitic diseases such as malaria, sleeping sickness and leishmania. in the search for genes encoding proteins involved in the antiparasitic response, we have used the protozoan parasite octosporea muscaedomesticae for oral infections of adult drosophila melanogaster. to identify parasite-specific response molecules, other flies were exposed to virus, bacteria or fungi in parallel. analysis of gene expression patterns after 24 h of microbial challeng ... | 2004 | 14749722 |
| integration of environmental and host-derived signals with quorum sensing during plant-microbe interactions. | many plant-associated microbes use secreted autoinducer molecules, including n-acylhomoserine lactones (ahls), to regulate diverse behaviours in association with their population density (quorum sensing). often, these responses are affected by environmental conditions, including the presence of other ahl-producing bacterial species. in addition, plant-derived metabolites, including products that arise as a direct result of the bacterial infection, may profoundly influence ahl-regulated behaviour ... | 2004 | 14764105 |
| norm, an erwinia amylovora multidrug efflux pump involved in in vitro competition with other epiphytic bacteria. | blossoms are important sites of infection for erwinia amylovora, the causal agent of fire blight of rosaceous plants. before entering the tissue, the pathogen colonizes the stigmatic surface and has to compete for space and nutrient resources within the epiphytic community. several epiphytes are capable of synthesizing antibiotics with which they antagonize phytopathogenic bacteria. here, we report that a multidrug efflux transporter, designated norm, of e. amylovora confers tolerance to the tox ... | 2004 | 14766544 |
| insecticidal bacillus thuringiensis silences erwinia carotovora virulence by a new form of microbial antagonism, signal interference. | it is commonly known that bacteria may produce antibiotics to interfere with the normal biological functions of their competitors in order to gain competitive advantages. here we report that bacillus thuringiensis suppressed the quorum-sensing-dependent virulence of plant pathogen erwinia carotovora through a new form of microbial antagonism, signal interference. e. carotovora produces and responds to acyl-homoserine lactone (ahl) quorum-sensing signals to regulate antibiotic production and expr ... | 2004 | 14766576 |
| evaluation of colilert-18 for detection of coliforms and eschericha coli in subtropical freshwater. | the accuracy of colilert-18 as a test for coliforms and escherichia coli in subtropical freshwater was evaluated by using api 20e strips and fatty acid methyl ester analysis. the false-positive and -negative rates of detection were 7.4 and 3.5%, respectively, for e. coli and 9.6 and 6.3%, respectively, for coliforms. | 2004 | 14766614 |
| microbial transformation of pyrethroid insecticides in aqueous and sediment phases. | recent studies showed that synthetic pyrethroids (sps) can move via surface runoff into aquatic systems. fifty-six of sp-degrading bacteria strains were isolated from contaminated sediments, of which six were evaluated for their ability to transform bifenthrin and permethrin in the aqueous phase and bifenthrin in the sediment phase. in the aqueous phase, bifenthrin was rapidly degraded by strains of stenotrophomonas acidaminiphila, and the half-life (t1/2) was reduced from >700 h to 30 to 131 h. ... | 2004 | 14768859 |
| observations on the bacteriophagy of erwinia carotovora. | | 1951 | 14824108 |
| fermentation of galacturonic acid and glucose by a strain of erwinia carotovora. | | 1952 | 14955520 |
| characterization of atypical erwinia carotovora strains causing blackleg of potato in brazil. | to determine the characteristics of bacteria associated with the blackleg disease of potato in brazil and compare them with species and subspecies of pectolytic erwinia. | 2004 | 14962133 |
| antifungal activity of beta-asarone from rhizomes of acorus gramineus. | an antifungal substance was isolated from the extract of acorus gramineus using various chromatographic procedures. the antibiotic was identified as beta-asarone, cis-2,4,5-trimethoxy-1-propenylbenzene, on the basis of the high-resolution ei-mass, nmr, and uv spectral data. beta-asarone completely inhibited mycelial growth of some plant pathogenic fungi, cladosporium cucumerinum,colletotrichum orbiculare, magnaporthe grisea, and pythium ultimum, in a range of 0.5-30 microg/ml. the growth of baci ... | 2004 | 14969530 |
| inactivation of a pseudomonas aeruginosa quorum-sensing signal by human airway epithelia. | mammalian airways protect themselves from bacterial infection by using multiple defense mechanisms including antimicrobial peptides, mucociliary clearance, and phagocytic cells. we asked whether airways might also target a key bacterial cell-cell communication system, quorum-sensing. the opportunistic pathogen pseudomonas aeruginosa uses two quorum-sensing molecules, n-(3-oxododecanoyl)-l-homoserine lactone (3oc12-hsl) and n-butanoyl-l-homoserine lactone (c4-hsl), to control production of extrac ... | 2004 | 14970327 |
| bacterial volatiles induce systemic resistance in arabidopsis. | plant growth-promoting rhizobacteria, in association with plant roots, can trigger induced systemic resistance (isr). considering that low-molecular weight volatile hormone analogues such as methyl jasmonate and methyl salicylate can trigger defense responses in plants, we examined whether volatile organic compounds (vocs) associated with rhizobacteria can initiate isr. in arabidopsis seedlings exposed to bacterial volatile blends from bacillus subtilis gb03 and bacillus amyloliquefaciens in937a ... | 2004 | 14976231 |
| one-step purification and kinetic properties of the recombinant l-asparaginase from erwinia carotovora. | ecar-lans, the recombinant l-asparaginase from erwinia carotovora, is a prospective therapeutic enzyme for leukaemia treatment. an efficient and economical scheme was developed for the purification, cloning and expression in eschericha coli of ecar-lans. more than 90% purity, complemented with 72% active enzyme recovery, was achieved with a single chromatographic purification step. the activity of purified l-asparaginase was 630 i.u./mg. the ecar-lans k (m) value was 98x10(-6) m for the main phy ... | 2004 | 15032742 |
| thermodependence of growth and enzymatic activities implicated in pathogenicity of two erwinia carotovora subspecies (pectobacterium spp.). | erwinia carotovora subsp. atroseptica and erwinia carotovora subsp. carotovora can cause substantial damage to economically important plant crops and stored products. the occurrence of the disease and the scale of the damage are temperature dependent. disease development consists first of active multiplication of the bacteria in the infection area and then production of numerous extracellular enzymes. we investigated the effects of various temperatures on these two steps. we assayed the specific ... | 2004 | 15052318 |
| genetic evidence that legionella pneumophila rpos modulates expression of the transmission phenotype in both the exponential phase and the stationary phase. | the opportunistic pathogen legionella pneumophila alternates between two states: replication within phagocytes and transmission between host amoebae or macrophages. in broth cultures that model this life cycle, during the replication period, csra inhibits expression of transmission traits. when nutrients become limiting, the alarmone (p)ppgpp accumulates and the sigma factors rpos and flia and the positive activators leta/s and lete promote differentiation to the transmissible form. here we show ... | 2004 | 15102753 |
| luxs is required for persistent pneumococcal carriage and expression of virulence and biosynthesis genes. | streptococcus pneumoniae causes several diseases, including otitis media, pneumonia, and meningitis. although little is known about the regulation of or how individual pneumococcal factors contribute to these disease states, there is evidence suggesting that some factors are regulated by a cell-density-dependent mechanism (quorum sensing). quorum sensing allows bacteria to couple transcription with changes in cell density; bacteria achieve this by sensing and responding to small diffusible signa ... | 2004 | 15102809 |
| the plant virus tomato spotted wilt tospovirus activates the immune system of its main insect vector, frankliniella occidentalis. | tospoviruses have the ability to infect plants and their insect vectors. tomato spotted wilt virus (tswv), the type species in the tospovirus genus, infects its most important insect vector, frankliniella occidentalis, the western flower thrips (wft). however, no detrimental effects on the life cycle or cytopathological changes have been reported in the wft after tswv infection, and relatively few viral particles can be observed even several days after infection. we hypothesized that tswv infect ... | 2004 | 15113877 |
| positive control of swarming, rhamnolipid synthesis, and lipase production by the posttranscriptional rsma/rsmz system in pseudomonas aeruginosa pao1. | in pseudomonas aeruginosa, the small rna-binding, regulatory protein rsma is a negative control element in the formation of several extracellular products (e.g., pyocyanin, hydrogen cyanide, pa-il lectin) as well as in the production of n-acylhomoserine lactone quorum-sensing signal molecules. rsma was found to control positively the ability to swarm and to produce extracellular rhamnolipids and lipase, i.e., functions contributing to niche colonization by p. aeruginosa. an rsma null mutant was ... | 2004 | 15126453 |
| genomic diversity of erwinia carotovora subsp. carotovora and its correlation with virulence. | we used genetic and biochemical methods to examine the genomic diversity of the enterobacterial plant pathogen erwinia carotovora subsp. carotovora. the results obtained with each method showed that e. carotovora subsp. carotovora strains isolated from one ecological niche, potato plants, are surprisingly diverse compared to related pathogens. a comparison of 23 partial mdh sequences revealed a maximum pairwise difference of 10.49% and an average pairwise difference of 2.13%, values which are mu ... | 2004 | 15128563 |
| negative cross-communication among wheat rhizosphere bacteria: effect on antibiotic production by the biological control bacterium pseudomonas aureofaciens 30-84. | phenazine antibiotic production in the biological control bacterium pseudomonas aureofaciens 30-84 is regulated in part via the phzr/phzi n-acyl homoserine lactone (ahl) system. previous work showed that a subpopulation of the wheat rhizosphere community positively affected phenazine gene expression in strain 30-84 via ahl signals (e. a. pierson, d. w. wood, j. a. cannon, f. m. blachere, and l. s. pierson iii, mol. plant-microbe interact. 11:1078-1084, 1998). in the present work, a second subpop ... | 2004 | 15128573 |
| the role of the jasmonate response in plant susceptibility to diverse pathogens with a range of lifestyles. | plants defend themselves against attack from insects and pathogens with various resistance strategies. the jasmonate and salicylate signaling pathways are two induced responses that protect plants against these attackers. knowledge of the range of organisms that are affected by each response is important for understanding how plants coordinate their defenses against multiple attackers and the generality of effect of different resistance mechanisms. the jasmonate response is known to protect plan ... | 2004 | 15133157 |
| fast screening method for detection of acyl-hsl-degrading soil isolates. | a reliable method was developed for screening of bacteria isolates capable of degrading acyl-hsls, the signal molecules in quorum-sensing-mediated processes of many proteobacteria. the microtiter assay was based on the use of a gfp-marked escherichia coli strain, which fluoresces upon the presence of acyl-hsls. measurement of gfp fluorescence with a molecular imager fx scanner (fluorometer) detected isolates capable of degrading acyl-hsls. the potential of this method was demonstrated by isolati ... | 2004 | 15134889 |
| partitioning of the variance in the growth parameters of erwinia carotovora on vegetable products. | the objective of this paper was to estimate and partition the variability in the microbial growth model parameters describing the growth of erwinia carotovora on pasteurised and non-pasteurised vegetable juice from laboratory experiments performed under different temperature-varying conditions. we partitioned the model parameter variance and covariance components into effects due to temperature profile and replicate using a maximum likelihood technique. temperature profile and replicate were tre ... | 2004 | 15135958 |
| transgenic potatoes expressing a novel cationic peptide are resistant to late blight and pink rot. | potato is the world's largest non-cereal crop. potato late blight is a pandemic, foliar wasting potato disease caused by phytophthora infestans, which has become highly virulent, fungicide resistant, and widely disseminated. similarly, fungicide resistant isolates of phytophthora erythroseptica, which causes pink rot, have also become an economic scourge of potato tubers. thus, an alternate, cost effective strategy for disease control has become an international imperative. here we describe a st ... | 2004 | 15198205 |
| endophytic bacterial communities of field-grown potato plants and their plant-growth-promoting and antagonistic abilities. | to study the effect of plant growth on potato-associated bacteria, the composition and properties of bacteria colonizing the endosphere of field-grown potato were analyzed by a multiphasic approach. the occurrence and diversity of potato-associated bacteria were monitored by a cultivation-independent approach, using terminal restriction fragment length polymorphism analysis of 16s rdna. the patterns obtained revealed a high heterogeneity of community composition and suggested the existence of pl ... | 2004 | 15213748 |
| comparative genomics of the methionine metabolism in gram-positive bacteria: a variety of regulatory systems. | regulation of the methionine biosynthesis and transport genes in bacteria is rather diverse and involves two rna-level regulatory systems and at least three dna-level systems. in particular, the methionine metabolism in gram-positive bacteria was known to be controlled by the s-box and t-box mechanisms, both acting on the level of premature termination of transcription. using comparative analysis of genes, operons and regulatory elements, we described the methionine metabolic pathway and the met ... | 2004 | 15215334 |
| isolation and characterisation of a class of carbohydrate oxidases from higher plants, with a role in active defence. | in a search for novel plant-derived antimicrobial proteins, we screened extracts from salicylic acid (sa)-treated lettuce and sunflower leaves. these extracts displayed very potent antimicrobial activity against a set of phytopathogens. characterisation of these extracts revealed that in both extracts, proteins of approximately 60 kda were responsible for the antimicrobial activity. further characterisation of these proteins and cloning of the respective cdnas revealed close homology to a range ... | 2004 | 15225281 |
| effects of natural and chemically synthesized furanones on quorum sensing in chromobacterium violaceum. | cell to cell signaling systems in gram-negative bacteria rely on small diffusible molecules such as the n-acylhomoserine lactones (ahl). these compounds are involved in the production of antibiotics, exoenzymes, virulence factors and biofilm formation. they belong to the class of furanone derivatives which are frequently found in nature as pheromones, flavor compounds or secondary metabolites. to obtain more information on the relation between molecular structure and quorum sensing, we tested a ... | 2004 | 15233843 |
| purification and characterization of two distinct metalloproteases secreted by the entomopathogenic bacterium photorhabdus sp. strain az29. | photorhabdus sp. strain az29 is symbiotic with an azorean nematode of the genus heterorhabditis in a complex that is highly virulent to insects even at low temperatures. the virulence of the bacteria is mainly attributed to toxins and bacterial enzymes secreted during parasitism. the bacteria secrete proteases during growth, with a peak at the end of the exponential growth phase. protease secretion was higher in cultures growing at lower temperatures. at 10 degrees c the activity was highest and ... | 2004 | 15240252 |
| presence of acylated homoserine lactones (ahls) and ahl-producing bacteria in meat and potential role of ahl in spoilage of meat. | quorum-sensing (qs) signals (n-acyl homoserine lactones [ahls]) were extracted and detected from five commercially produced vacuum-packed meat samples. ninety-six ahl-producing bacteria were isolated, and 92 were identified as enterobacteriaceae. hafnia alvei was the most commonly identified ahl-producing bacterium. thin-layer chromatographic profiles of supernatants from six h. alvei isolates and of extracts from spoiling meat revealed that the major ahl species had an r(f) value and shape simi ... | 2004 | 15240313 |
| a type ii protein secretory pathway required for levansucrase secretion by gluconacetobacter diazotrophicus. | the endophytic diazotroph gluconacetobacter diazotrophicus secretes a constitutively expressed levansucrase (lsda, ec 2.4.1.10) to utilize plant sucrose. lsda, unlike other extracellular levansucrases from gram-negative bacteria, is transported to the periplasm by a signal-peptide-dependent pathway. we identified an unusually organized gene cluster encoding at least the components lsdg, -o, -e, -f, -h, -i, -j, -l, -m, -n, and -d of a type ii secretory system required for lsda translocation acros ... | 2004 | 15262940 |
| genome sequence of the enterobacterial phytopathogen erwinia carotovora subsp. atroseptica and characterization of virulence factors. | the bacterial family enterobacteriaceae is notable for its well studied human pathogens, including salmonella, yersinia, shigella, and escherichia spp. however, it also contains several plant pathogens. we report the genome sequence of a plant pathogenic enterobacterium, erwinia carotovora subsp. atroseptica (eca) strain scri1043, the causative agent of soft rot and blackleg potato diseases. approximately 33% of eca genes are not shared with sequenced enterobacterial human pathogens, including s ... | 2004 | 15263089 |
| fungistatic and bacteriostatic activities of alkamides from heliopsis longipes roots: affinin and reduced amides. | this work demonstrates the fungistatic and bacteriostatic activities of affinin, the main alkamide of heliopsis longipes (gray) blake (asteraceae) roots and two alkamides obtained by catalytic reduction of affinin: n-isobutyl-2e-decenamide and n-isobutyl-decanamide. the bioactivity was tested against rhizoctonia solani groups ag3 and ag5, sclerotium rolfsii, sclerotium cepivorum, fusarium sp., vertcillium sp., phytopathogenic fungi; phytophthora infestans, a phytopathogenic chromista; saccharomy ... | 2004 | 15264902 |
| a hydrocarbon ruler measures palmitate in the enzymatic acylation of endotoxin. | the ability of enzymes to distinguish between fatty acyl groups can involve molecular measuring devices termed hydrocarbon rulers, but the molecular basis for acyl-chain recognition in any membrane-bound enzyme remains to be defined. pagp is an outer membrane acyltransferase that helps pathogenic bacteria to evade the host immune response by transferring a palmitate chain from a phospholipid to lipid a (endotoxin). pagp can distinguish lipid acyl chains that differ by a single methylene unit, in ... | 2004 | 15272304 |
| the bacterial type iii secretion system-associated pilin hrpa has an unusually long mrna half-life. | secondary structures affect mrna stability and may play a role in protein secretion. we have studied the mrna of hrpa, which codes for the major structural unit of the type iii secretion system-associated pilus of pseudomonas syringae pv. tomato, erwinia carotovora and pseudomonas syringae pv. phaseolicola. we show that hrpa mrna has an unusually long half-life, approximately 33-47 min. we mapped regions in the transcript that affected hrpa mrna accumulation. apparently, sequences at both 5' and ... | 2004 | 15280045 |
| assessment of genetic variability of haploids extracted from tetraploid (2n = 4x = 48) solanum tuberosum. | the objectives of this study were to assess the genetic variability of haploids (2n = 2x = 24) extracted from tetraploid solanum tuberosum through 4x x 2x crosses with solanum phureja. molecular and phenotypic analyses were performed to fingerprint the genotypes used and to evaluate their potential use in breeding programs. aflp analysis revealed the presence of specific bands derived from the tetraploid seed parent s. phureja, as well as ex novo originated bands. on average, 210 bands were visu ... | 2004 | 15284867 |
| characterization of metabolic pathway of linoleic acid 9-hydroperoxide in cytosolic fraction of potato tubers and identification of reaction products. | potato tubers are shown to contain a unique lipoxygenase pathway to form 9-hydroperoxy-10,12-octadecadienoic acid (9-hpode) from linoleic acid. here, we report the metabolic pathway of 9-hpode in the cytosolic fraction and the characterization of enzymes involved in the conversion of metabolites. the analysis of enzymatic reaction products at ph 5.5 revealed the formation of 9-keto-10,12-octadecadienoic acid, 9-hydroxy-10,12-octadecadienoic acid, 9,10-epoxy-11-hydroxy-12-octadecenoic acid, 9,10, ... | 2004 | 15304744 |
| potato plants genetically modified to produce n-acylhomoserine lactones increase susceptibility to soft rot erwiniae. | many gram-negative bacteria employ n-acylhomoserine lactones (ahl) to regulate diverse physiological processes in concert with cell population density (quorum sensing [qs]). in the plant pathogen erwinia carotovora, the ahl synthesized via the cari/expi genes are responsible for regulating the production of secreted plant cell wall-degrading exoenzymes and the antibiotic carbapen-3-em carboxylic acid. we have previously shown that targeting the product of an ahl synthase gene (yeni) from yersini ... | 2004 | 15305609 |
| plant defense gene promoter enhances the reliability of shiva-1 gene-induced resistance to soft rot disease in potato. | pal5, a tomato (lycopersicon esculentum mill.) plant defense gene that encodes phenylalanine ammonia-lyase, is known to respond to a variety of environmental stresses including pathogen infection and wounding. a shiva-1 gene recombinant that encodes a small synthetic antibacterial peptide under the pal5 gene promoter was transformed into potato (solanum tuberosum l.) and its ability to induce resistance to erwinia carotovora was compared with a construct under the control of the constitutive and ... | 2004 | 15309537 |
| identification of a quinone-sensitive redox switch in the arcb sensor kinase. | escherichia coli senses and signals anoxic or low redox conditions in its growth environment by the arc two-component system. under anaerobic conditions, the arcb sensor kinase autophosphorylates and transphosphorylates arca, a global transcriptional regulator that controls the expression of numerous operons involved in respiratory or fermentative metabolism. under aerobic conditions, the kinase activity of arcb is inhibited by the quinone electron carriers that act as direct negative signals. h ... | 2004 | 15326287 |
| comparison of atpase-encoding type iii secretion system hrcn genes in biocontrol fluorescent pseudomonads and in phytopathogenic proteobacteria. | type iii protein secretion systems play a key role in the virulence of many pathogenic proteobacteria, but they also occur in nonpathogenic, plant-associated bacteria. certain type iii protein secretion genes (e.g., hrcc) have been found in pseudomonas sp. strain sbw25 (and other biocontrol pseudomonads), but other type iii protein secretion genes, such as the atpase-encoding gene hrcn, have not been found. using both colony hybridization and a pcr approach, we show here that hrcn is nevertheles ... | 2004 | 15345390 |
| localization and characterization of two novel genes encoding stereospecific dioxygenases catalyzing 2(2,4-dichlorophenoxy)propionate cleavage in delftia acidovorans mc1. | two novel genes, rdpa and sdpa, encoding the enantiospecific alpha-ketoglutarate dependent dioxygenases catalyzing r,s-dichlorprop cleavage in delftia acidovorans mc1 were identified. significant similarities to other known genes were not detected, but their deduced amino acid sequences were similar to those of other alpha-ketoglutarate dioxygenases. rdpa showed 35% identity with taud of pseudomonas aeruginosa, and sdpa showed 37% identity with tfda of ralstonia eutropha jmp134. the functionally ... | 2004 | 15345421 |
| amine-synthesizing enzyme n-substituted formamide deformylase: screening, purification, characterization, and gene cloning. | n-substituted formamide was produced through the hydration of an isonitrile by isonitrile hydratase in the isonitrile metabolism. the former compound was further degraded by a microorganism, strain f164, which was isolated from soil through an acclimatization culture. the n-substituted formamide-degrading microorganism was identified as arthrobacter pascens. the microbial degradation was found to proceed through an enzymatic reaction, the n-substituted formamide being hydrolyzed to yield the cor ... | 2004 | 15358859 |
| use of a pooled transposon mutation grid to demonstrate roles in disease development for erwinia carotovora subsp. atroseptica putative type iii secreted effector (dspe/a) and helper (hrpn) proteins. | soft rot erwinia spp., like other closely related plant pathogens, possess a type iii secretion system (ttss) (encoded by the hrp gene cluster) implicated in disease development. we report the sequence of the entire hrp gene cluster and adjacent dsp genes in erwinia carotovora subsp. atroseptica scri1039. the cluster is similar in content and structural organization to that in e. amylovora. however, eight putative genes of unknown function located within the e. carotovora subsp. atroseptica clus ... | 2004 | 15384484 |
| quorum quenching: enzymatic disruption of n-acylhomoserine lactone-mediated bacterial communication in burkholderia thailandensis. | many species of gram-negative bacteria communicate by synthesizing, secreting, and responding to n-acylhomoserine lactones (ahls), a mechanism termed quorum sensing. several investigations have characterized numerous ahl-degrading enzymes (aiia lactonases) encoded by environmental isolates of bacillus spp. the burkholderia thailandensis quorum system is comprised of at least three ahl synthases (ahss) and five transcriptional regulators belonging to the luxir class of proteins. expression of the ... | 2004 | 15466564 |
| identification of an antibacterial compound, benzylideneacetone, from xenorhabdus nematophila against major plant-pathogenic bacteria. | an entomopathogenic bacterium, xenorhabdus nematophila, is known to have potent antibiotic activities to maintain monoxenic condition in its insect host for effective pathogenesis and ultimately for optimal development of its nematode symbiont, steinernema carpocapsae. in this study we assess its antibacterial activity against plant-pathogenic bacteria and identify its unknown antibiotics. the bacterial culture broth had significant antibacterial activity that increased with development of the b ... | 2004 | 15476972 |
| 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 |
| a drosophila p38 orthologue is required for environmental stress responses. | the p38 mitogen-activated protein kinase (mapk) cascade is an evolutionarily conserved signalling mechanism involved in processes as diverse as apoptosis, cell fate determination, immune function and stress response. aberrant p38 signalling has been implicated in many human diseases, including heart disease, cancer, arthritis and neurodegenerative diseases. to further understand the role of p38 in these processes, we generated a drosophila strain that is null for the d-p38a gene. mutants are hom ... | 2004 | 15514678 |
| in vivo production of active nickel superoxide dismutase from prochlorococcus marinus mit9313 is dependent on its cognate peptidase. | metal-dependent superoxide dismutases (sods) with a specific requirement for a manganese or iron ion for catalytic activity and copper- and zinc-dependent enzymes are essential for detoxification of superoxide anion radicals. genome sequence analyses predict the existence of a nickel-dependent enzyme (nisod) as the unique sod in oxygen-evolving marine cyanobacteria. nisod activity was observed in escherichia coli when sodn and sodx (encoding a putative peptidase) from prochlorococcus marinus mit ... | 2004 | 15516600 |
| ultrastructural alterations of erwinia carotovora subsp. atroseptica caused by treatment with aluminum chloride and sodium metabisulfite. | aluminum and bisulfite salts inhibit the growth of several fungi and bacteria, and their application effectively controls potato soft rot caused by erwinia carotovora. in an effort to understand their inhibitory action, ultrastructural changes in erwinia carotovora subsp. atroseptica after exposure (0 to 20 min) to different concentrations (0.05, 0.1, and 0.2 m) of these salts were examined by using transmission electron microscopy. plasma membrane integrity was evaluated by using the sytox gree ... | 2004 | 15528547 |
| peptidoglycan recognition protein (pgrp)-le and pgrp-lc act synergistically in drosophila immunity. | in innate immunity, pattern recognition molecules recognize cell wall components of microorganisms and activate subsequent immune responses, such as the induction of antimicrobial peptides and melanization in drosophila. the diaminopimelic acid (dap)-type peptidoglycan potently activates imd-dependent induction of antibacterial peptides. peptidoglycan recognition protein (pgrp) family members act as pattern recognition molecules. pgrp-lc loss-of-function mutations affect the imd-dependent induct ... | 2004 | 15538387 |
| ralstonia solanacearum iron scavenging by the siderophore staphyloferrin b is controlled by phca, the global virulence regulator. | phca is a transcriptional regulator that activates expression of multiple virulence genes in the plant pathogen ralstonia solanacearum. relative to their wild-type parents, phca mutants overproduced iron-scavenging activity detected with chrome azurol s siderophore detection medium. transposon mutagenesis of strain aw1-pc (phca1) generated strain gb6, which was siderophore negative but retained weak iron-scavenging activity. the ssd gene inactivated in gb6 encodes a protein similar to group iv a ... | 2004 | 15547261 |
| the n terminus of bacterial elongation factor tu elicits innate immunity in arabidopsis plants. | innate immunity is based on the recognition of pathogen-associated molecular patterns (pamps). here, we show that elongation factor tu (ef-tu), the most abundant bacterial protein, acts as a pamp in arabidopsis thaliana and other brassicaceae. ef-tu is highly conserved in all bacteria and is known to be n-acetylated in escherichia coli. arabidopsis plants specifically recognize the n terminus of the protein, and an n-acetylated peptide comprising the first 18 amino acids, termed elf18, is fully ... | 2004 | 15548740 |
| antagonistic interaction between abscisic acid and jasmonate-ethylene signaling pathways modulates defense gene expression and disease resistance in arabidopsis. | the plant hormones abscisic acid (aba), jasmonic acid (ja), and ethylene are involved in diverse plant processes, including the regulation of gene expression during adaptive responses to abiotic and biotic stresses. previously, aba has been implicated in enhancing disease susceptibility in various plant species, but currently very little is known about the molecular mechanisms underlying this phenomenon. in this study, we obtained evidence that a complex interplay between aba and ja-ethylene sig ... | 2004 | 15548743 |
| involvement of n-acylhomoserine lactones throughout plant infection by erwinia carotovora subsp. atroseptica (pectobacterium atrosepticum). | erwinia carotovora subsp. atroseptica is responsible for potato blackleg disease in the field and tuber soft rot during crop storage. the process leading to the disease occurs in two phases: a primary invasion step followed by a maceration step. bacteria-to-bacteria communication is associated with a quorum-sensing (qs) process based on the production of n-acylhomoserine lactones (hsl). the role of hsl throughout plant infection was analyzed. to this purpose, hsl produced by a specific e. caroto ... | 2004 | 15553252 |
| characterization of a defensin from the sand fly phlebotomus duboscqi induced by challenge with bacteria or the protozoan parasite leishmania major. | antimicrobial peptides are major components of the innate immune response of epithelial cells. in insect vectors, these peptides may play a role in the control of gut pathogens. we have analyzed antimicrobial peptides produced by the sand fly phlebotomus duboscqi, after challenge by injected bacteria or feeding with bacteria or the protozoan parasite leishmania major. a new hemolymph peptide with antimicrobial activity was identified and shown to be a member of the insect defensin family. intere ... | 2004 | 15557638 |
| identification of a novel virulence factor in burkholderia cenocepacia h111 required for efficient slow killing of caenorhabditis elegans. | burkholderia cenocepacia h111, which was isolated from a cystic fibrosis patient, employs a quorum-sensing (qs) system, encoded by cep, to control the expression of virulence factors as well as the formation of biofilms. the qs system is thought to ensure that pathogenic traits are expressed only when the bacterial population density is high enough to overwhelm the host before it is able to mount an efficient response. while the wild-type strain effectively kills the nematode caenorhabditis eleg ... | 2004 | 15557647 |
| [genetic regulation of pathogenicity and virulence factors in bacteria erwinia carotovora subsp. atroseptica: identification of kdud gene]. | a mutant that cannot utilize pectin substances of plant cell walls was obtained via insertion of mini-mini-tn5xyle transposon into the chromosome of phytopathogenic bacteria erwinia carotovora subsp. atroseptica. the inability of mutant cells to utilize these substrates was caused by a failure to accomplish the catabolism of unsaturated digalacturonic acid (uda). study of enzymatic activities has established that mutant bacteria lost the ability to produce 2,5-diketo-3-deoxygluconate dehydrogena ... | 2004 | 15559145 |
| [genetic regulation of pathogenicity and virulence factors in bacteria erwinia carotovora subsp. atroseptica: phenotypic characteristic of bacteria with the mutant kdud gene]. | in contrast to the closely related bacteria erwinia chrysanthemi, bacteria erwinia carotovora subsp. atroseptica produce lower levels of main pathogenicity and virulence factors (pectate lyases, cellulases, and proteases) in the presence of pectins. this effect was shown to be connected with the accumulation of the intermediate product of intracellular degradation of these substances, 2,5-diketo-3-deoxygluconate (dk2). the presence of dk2 in the culture broth of mutant bacteria, connected to its ... | 2004 | 15559146 |
| analysis of bgl operon structure and characterization of beta-glucosidase from pectobacterium carotovorum subsp. carotovorum ly34. | a putative bgl operon of pectobacterium carotovorum subsp. carotovorum ly34 (pcc ly34) was isolated. sequence analysis of the 5,557 bp cloned dna fragment (accession no. ay542524) showed three open reading frames (bglt, bglp, and bglb) predicted to encode 287, 633, and 468 amino acid proteins respectively. bglt and bglp orfs show high similarity to that of the pectobacterium chrysanthemi arbg antiterminator and arbf permease respectively. also, the latter contains most residues important for pho ... | 2004 | 15564664 |
| antibacterial activity of cichorium intybus. | antibacterial activity of the water, ethanol and ethyl acetate extracts of cichorium intybus was investigated. all the tested extracts showed antibacterial activity, the ethyl acetate extract being the most active. water extract inhibits agrobacterium radiobacter sp. tumefaciens, erwinia carotovora, pseudomonas fluorescens and p. aeruginosa. | 2004 | 15567253 |
| identification and characterization of nip, necrosis-inducing virulence protein of erwinia carotovora subsp. carotovora. | erwinia carotovora subsp. carotovora is a gram-negative bacterium that causes soft rot disease of many cultivated crops. when a collection of e. carotovora subsp. carotovora isolates was analyzed on a southern blot using the harpin-encoding gene hrpn as probe, several harpinless isolates were found. regulation of virulence determinants in one of these, strain scc3193, has been characterized extensively. it is fully virulent on potato and in arabidopsis thaliana. an rpos (sigmas) mutant of scc319 ... | 2004 | 15597742 |
| chlorophyllase 1, a damage control enzyme, affects the balance between defense pathways in plants. | accumulation of reactive oxygen species (ros) is central to plant response to several pathogens. one of the sources of ros is the chloroplast because of the photoactive nature of the chlorophylls. chlorophyllase 1 (encoded by atclh1) of arabidopsis thaliana is quickly induced after tissue damage (e.g., caused by the bacterial necrotroph erwinia carotovora or the necrotrophic fungus alternaria brassicicola). rna interference silencing of atclh1 resulted in failure to degrade free chlorophyll afte ... | 2004 | 15598807 |
| posttranscriptional repression of gacs/gaca-controlled genes by the rna-binding protein rsme acting together with rsma in the biocontrol strain pseudomonas fluorescens cha0. | in the plant-beneficial soil bacterium pseudomonas fluorescens cha0, the production of biocontrol factors (antifungal secondary metabolites and exoenzymes) is controlled at a posttranscriptional level by the gacs/gaca signal transduction pathway involving rna-binding protein rsma as a key regulatory element. this protein is assumed to bind to the ribosome-binding site of target mrnas and to block their translation. rsma-mediated repression is relieved at the end of exponential growth by two gacs ... | 2005 | 15601712 |
| the wrky transcription factor superfamily: its origin in eukaryotes and expansion in plants. | wrky proteins are newly identified transcription factors involved in many plant processes including plant responses to biotic and abiotic stresses. to date, genes encoding wrky proteins have been identified only from plants. comprehensive search for wrky genes in non-plant organisms and phylogenetic analysis would provide invaluable information about the origin and expansion of the wrky family. | 2005 | 15629062 |
| altering substrate chain length specificity of an acylhomoserine lactone synthase in bacterial communication. | quorum sensing mediated by specific signal compounds (autoinducers) allows bacteria to monitor their cell density and enables a synchronized regulation of target gene sets. the best studied group of autoinducers are the acylhomoserine lactones (ahsls), which are central to the regulation of virulence in many plant and animal pathogens. variation of the acyl side chain of the ahsls underlies the observed species specificity of this communication system. here we show that even different strains of ... | 2005 | 15634689 |
| interactions between oral bacteria: inhibition of streptococcus mutans bacteriocin production by streptococcus gordonii. | streptococcus mutans has been recognized as an important etiological agent in human dental caries. some strains of s. mutans also produce bacteriocins. in this study, we sought to demonstrate that bacteriocin production by s. mutans strains gs5 and bm71 was mediated by quorum sensing, which is dependent on a competence-stimulating peptide (csp) signaling system encoded by the com genes. we also demonstrated that interactions with some other oral streptococci interfered with s. mutans bacteriocin ... | 2005 | 15640209 |
| degradation of acyl-homoserine lactone molecules by acinetobacter sp. strain c1010. | a bacterium c1010, isolated from the rhizospheres of cucumbers in fields in korea, degraded the microbial quorum-sensing molecules, hexanoyl homoserine lactone (hhsl), and octadecanoyl homoserine lactone (ohsl). morphological characteristics and 16s rrna sequence analysis identified c1010 as acinetobacter sp. strain c1010. this strain was able to degrade the acyl-homoserine lactones (ahls) produced by the biocontrol bacterium, pseudomonas chlororaphis o6, and a phytopathogenic bacterium, burkhol ... | 2004 | 15644910 |
| use of 1,4-naphthoquinones for control of erwinia carotovora. | the antimicrobial effect of 5 naphthoquinones was tested against the phytopathogenic bacteria erwinia carotovora. disk diffusion tests and determination of minimal inhibitory concentrations (mic) indicate that the compound naphthazarin (ntz) has the best antibacterial activity among the naphthoquinones tested. studies on the mode of action indicate the effect of ntz was bactericidal at 10 microg/ml. when cultivation was done in the presence of sodium ascorbate, the restoration of e. carotovora g ... | 2004 | 15644912 |
| 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 |
| bioactive ellagitannins from cunonia macrophylla, an endemic cunoniaceae from new caledonia. | chemical study of cunonia macrophylla, a new caledonian cunoniaceae, based on bioactive effects of a crude methanol extract of the leaves, detected bioactive tannins for the first time in this plant family. these ellagitannins have been identified as ellagic acid-4-o-beta-d-xylopyranoside (6), mallorepanin (3), mallotinic acid (1) along with corilagin (2), chebulagic acid (4), ellagic acid (5) and gallic acid (7) and have been shown to possess antimicrobial activity and to inhibit xanthine oxida ... | 2005 | 15652581 |
| ectopic expression of anthocyanin 5-o-glucosyltransferase in potato tuber causes increased resistance to bacteria. | the principal goal of this paper was to investigate the significance of anthocyanin 5-o-glucosyltransferase (5-ugt) for potato tuber metabolism. the ectopic expression of a 5-ugt cdna in the tuber improved the plant's defense against pathogen infection. the resistance of transgenic lines against erwinia carotovora subsp. carotovora was about 2-fold higher than for nontransformed plants. in most cases the pathogen resistance was accompanied by a significant increase in tuber yield. to investigate ... | 2005 | 15656661 |
| carbapenem antibiotic biosynthesis in erwinia carotovora is regulated by physiological and genetic factors modulating the quorum sensing-dependent control pathway. | erwinia carotovora produces the beta-lactam antibiotic, carbapenem, in response to a quorum sensing signalling molecule, n-(3-oxohexanoyl)-l-homoserine lactone (ohhl). we have mapped the ohhl-dependent promoter upstream of the first of the biosynthetic genes, cara. we have also analysed the effect on this promoter of the known genetic regulators of carbapenem expression, carr, cari (encoding homologues of luxr and luxi respectively) and hor (encoding a slya/marr-like transcriptional regulator). ... | 2005 | 15659168 |
| genome-wide transcriptional response of chemostat-cultured escherichia coli to zinc. | zinc is an essential trace metal ion for growth, but an excess of zn is toxic and microorganisms express diverse resistance mechanisms. to understand global bacterial responses to excess zn, we conducted transcriptome profiling experiments comparing escherichia coli mg1655 grown under control conditions and cells grown with a toxic, sublethal znso4 concentration (0.2 mm). cultures were grown in a defined medium lacking inorganic phosphate, permitting maximum zn bioavailability, and in glycerol-l ... | 2005 | 15659689 |
| antibacterial activity of seed proteins of robinia pseudoacacia. | a low molecular weight cationic peptide was isolated from robinia pseudoacacia seed and tested in vitro against seven bacteria (corynebacterium michiganense, staphylococcus aureus, bacillus subtilis, erwinia carotovora subsp. carotovora, pseudomonas syringae pv syringae, xanthomonas campestris pv campestris, and escherichia coli). the peptide inhibited the growth of the tested strains. the effective concentrations required for 50% inhibition of bacterial growth ranged between 20 and 120 microg m ... | 2005 | 15664465 |
| novel mutants of erwinia carotovora subsp. carotovora defective in the production of plant cell wall degrading enzymes generated by mu transpososome-mediated insertion mutagenesis. | as in erwinia carotovora subsp. carotovora the regulation details of the main virulence factors, encoding extracellular enzymes that degrade the plant cell wall, is only rudimentally understood, we performed a genetic screen to identify novel candidate genes involved in the process. initially, we used mu transpososome-mediated mutagenesis approach to generate a comprehensive transposon insertion mutant library of ca. 10000 clones and screened the clones for the loss of extracellular enzyme produ ... | 2005 | 15668006 |
| potential ecotoxicological implication of methyl tert-butyl ether (mtbe) spills in the environment. | streptomyceticidal activity of methyl tert-butyl ether (mtbe) elucidated for the first time. adverse effect of mtbe, the gasoline additive, against 11 soil inhabitant streptomyces spp. isolates was investigated. mtbe, an octane enhancer is added to gasoline to reduce atmospheric concentrations of carbon monoxide and ozone. it contaminates soil and groundwater by fuel leaks and spills. streptomyces spp. are of the major contributors to the biological buffering of soils by exerting beneficial and ... | 2004 | 15673212 |
| the genome sequence of xanthomonas oryzae pathovar oryzae kacc10331, the bacterial blight pathogen of rice. | the nucleotide sequence was determined for the genome of xanthomonas oryzae pathovar oryzae (xoo) kacc10331, a bacterium that causes bacterial blight in rice (oryza sativa l.). the genome is comprised of a single, 4 941 439 bp, circular chromosome that is g + c rich (63.7%). the genome includes 4637 open reading frames (orfs) of which 3340 (72.0%) could be assigned putative function. orthologs for 80% of the predicted xoo genes were found in the previously reported x.axonopodis pv. citri (xac) a ... | 2005 | 15673718 |
| repeat-length-independent broad-spectrum shuffling, a novel method of generating a random chimera library in vivo. | we describe a novel method of random chimeragenesis based on highly frequent deletion formation in the escherichia coli ssb-3 strain and a deletion-directed chimera selection system that uses the rpsl(+) gene as a reporter. it enables the selection of chimeras without target gene expression and can therefore be applied to cytotoxic targets. when this system was applied to phospholipase d genes from streptomyces septatus th-2 and streptomyces halstedii subsp. scabies k6 (examples of cytotoxic tar ... | 2005 | 15691927 |
| protein domains and architectural innovation in plant-associated proteobacteria. | evolution of new complex biological behaviour tends to arise by novel combinations of existing building blocks. the functional and evolutionary building blocks of the proteome are protein domains, the function of a protein being dependent on its constituent domains. we clustered completely-sequenced proteomes of prokaryotes on the basis of their protein domain content, as defined by pfam (release 16.0). this revealed that, although there was a correlation between phylogeny and domain content, ot ... | 2005 | 15715905 |
| screening for quorum-sensing inhibitors (qsi) by use of a novel genetic system, the qsi selector. | with the widespread appearance of antibiotic-resistant bacteria, there is an increasing demand for novel strategies to control infectious diseases. furthermore, it has become apparent that the bacterial life style also contributes significantly to this problem. bacteria living in the biofilm mode of growth tolerate conventional antimicrobial treatments. the discovery that many bacteria use quorum-sensing (qs) systems to coordinate virulence and biofilm development has pointed out a new, promisin ... | 2005 | 15716452 |
| hosa, a member of the slya family, regulates motility in enteropathogenic escherichia coli. | in enteropathogenic and enterohemorraghic escherichia coli (epec and ehec), two members of the slya family of transcriptional regulators have been identified as slya. western blot analysis of the wild type and the corresponding hosa and slya deletion mutants indicated that slya and hosa are distinct proteins whose expression is not interdependent. of 27 different e. coli strains (epec, ehec, enteroinvasive, enteroaggregative, uropathogenic, and commensal) examined, 14 were positive for both gene ... | 2005 | 15731069 |