Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| a subtilisin-like serine protease involved in the regulation of stomatal density and distribution in arabidopsis thaliana. | stomata are specialized cellular structures in the epidermis of aerial plant organs that control gas exchange (h(2)o release and co(2) uptake) between leaves and the atmosphere by modulating the aperture of a pore flanked by two guard cells. stomata are nonrandomly distributed, and their density is controlled by endogenous and environmental factors. to gain insight into the molecular mechanisms regulating stomatal distribution, arabidopsis thaliana mutants with altered stomatal characteristics w ... | 2000 | 10809670 |
| cloning and expression of ntnd, encoding a novel nad(p)(+)-independent 4-nitrobenzyl alcohol dehydrogenase from pseudomonas sp. strain tw3. | pseudomonas sp. strain tw3 is able to metabolize 4-nitrotoluene to 4-nitrobenzoate and toluene to benzoate aerobically via a route analogous to the upper pathway of the tol plasmids. we report the cloning and characterization of a benzyl alcohol dehydrogenase gene (ntnd) which encodes the enzyme for the catabolism of 4-nitrobenzyl alcohol and benzyl alcohol to 4-nitrobenzaldehyde and benzaldehyde, respectively. the gene is located downstream of the previously reported ntn gene cluster. ntnd bear ... | 2000 | 10809692 |
| prey range characterization, ribotyping, and diversity of soil and rhizosphere bdellovibrio spp. isolated on phytopathogenic bacteria. | thirty new bdellovibrio strains were isolated from an agricultural soil and from the rhizosphere of plants grown in that soil. using a combined molecular and culture-based approach, we found that the soil bdellovibrios included subpopulations of organisms that differed from rhizosphere bdellovibrios. thirteen soil and seven common bean rhizosphere bdellovibrio strains were isolated when pseudomonas corrugata was used as prey; seven and two soil strains were isolated when erwinia carotovora subsp ... | 2000 | 10831412 |
| the exbd2 gene as well as the iron-uptake genes tonb, exbb and exbd1 of xanthomonas campestris pv. campestris are essential for the induction of a hypersensitive response on pepper (capsicum annuum). | the tonb, exbb and exbd1 genes of xanthomonas campestris pv. campestris are essential for ferric iron uptake. in contrast, the exbd2 gene located in the same gene cluster is not essential. mutational analysis revealed that the ferric-iron-uptake genes tonb, exbb and exbd1 are necessary for the induction of a hypersensitive response (hr) on the nonhost plant pepper (capsicum annuum) and the induction of typical black rot symptoms on the host plant cauliflower (brassica oleracea). again, the exbd2 ... | 2000 | 10832632 |
| identification of sinorhizobium meliloti genes regulated during symbiosis. | rna fingerprinting by arbitrarily primed pcr was used to isolate sinorhizobium meliloti genes regulated during the symbiotic interaction with alfalfa (medicago sativa). sixteen partial cdnas were isolated whose corresponding genes were differentially expressed between symbiotic and free-living conditions. thirteen sequences corresponded to genes up-regulated during symbiosis, whereas three were instead repressed during establishment of the symbiotic interaction. seven cdnas corresponded to known ... | 2000 | 10850975 |
| role of the dpr product in oxygen tolerance in streptococcus mutans. | we have previously identified and characterized the alkyl hydroperoxide reductase of streptococcus mutans, which consists of two components, nox-1 and ahpc. deletion of both nox-1 and ahpc had no effect on the sensitivity of s. mutans to cumene hydroperoxide or h(2)o(2), implying that the existence of another antioxidant system(s) independent of the nox-1-ahpc system compensates for the deficiency. here, a new antioxidant gene (dpr for dps-like peroxide resistance gene) was isolated from the s. ... | 2000 | 10850989 |
| marinomonas mediterranea mmb-1 transposon mutagenesis: isolation of a multipotent polyphenol oxidase mutant. | marinomonas mediterranea is a melanogenic marine bacterium expressing a multifunctional polyphenol oxidase (ppo) able to oxidize substrates characteristic for laccases and tyrosinases, as well as produce a classical tyrosinase. a new and quick method has been developed for screening laccase activity in culture plates to detect mutants differentially affected in this ppo activity. transposon mutagenesis has been applied for the first time to m. mediterranea by using different minitransposons load ... | 2000 | 10850991 |
| mutations in oxyr resulting in peroxide resistance in xanthomonas campestris. | a spontaneous xanthomonas campestris pv. phaseoli h(2)o(2)-resistant mutant emerged upon selection with 1 mm h(2)o(2). in this report, we show that growth of this mutant under noninducing conditions gave high levels of catalase, alkyl hydroperoxide reductase (ahpc and ahpf), and oxyr. the h(2)o(2) resistance phenotype was abolished in oxyr-minus derivatives of the mutant, suggesting that elevated levels and mutations in oxyr were responsible for the phenotype. nucleotide sequence analysis of the ... | 2000 | 10851004 |
| virulence of the phytopathogen pseudomonas syringae pv. maculicola is rpon dependent. | we cloned the rpon (ntra and glnf) gene encoding sigma(54) from the phytopathogen pseudomonas syringae pv. maculicola strain es4326. the p. syringae es4326 rpon gene complemented pseudomonas aeruginosa, escherichia coli, and klebsiella aerogenes rpon mutants for a variety of rpon mutant phenotypes, including the inability to utilize nitrate as sole nitrogen source. dna sequence analysis of the p. syringae es4326 rpon gene revealed that the deduced amino acid sequence was most similar (86% identi ... | 2000 | 10852883 |
| the alternative sigma factor rpon is required for hrp activity in pseudomonas syringae pv. maculicola and acts at the level of hrpl transcription. | beta-glucuronidase (uida) reporter gene fusions were constructed for the hrpz, hrpl, and hrps genes from the phytopathogen pseudomonas syringae pv. maculicola strain es4326. these reporters, as well as an avrrpt2-uida fusion, were used to measure transcriptional activity in es4326 and a es4326 rpon mutant. rpon was required for the expression of avrrpt2, hrpz, and hrpl in vitro in minimal media and in vivo when infiltrated into arabidopsis thaliana leaves. in contrast, the expression of hrps was ... | 2000 | 10852884 |
| importance of holotoxin assembly in ptl-mediated secretion of pertussis toxin from bordetella pertussis. | we examined the structural components of pertussis toxin that are required for efficient export from bordetella pertussis via the ptl system, a member of the type iv family of macromolecular transporters. first, we constructed a strain of b. pertussis that contains a functional ptl system but does not produce pertussis toxin. plasmids which express either the s1 subunit or the b oligomer were then introduced into this strain. we found that the b oligomer of the toxin is not secreted in the absen ... | 2000 | 10858221 |
| influence of deletions within domain ii of exotoxin a on its extracellular secretion from pseudomonas aeruginosa. | pseudomonas aeruginosa is a gram-negative bacterium that secretes many proteins into the extracellular medium via the xcp machinery. this pathway, conserved in gram-negative bacteria, is called the type ii pathway. the exoproteins contain information in their amino acid sequence to allow targeting to their secretion machinery. this information may be present within a conformational motif. the nature of this signal has been examined for p. aeruginosa exotoxin a (pe). previous studies failed to id ... | 2000 | 10869085 |
| bioaugmentation of activated sludge by an indigenous 3-chloroaniline-degrading comamonas testosteroni strain, i2gfp. | a strain identified as comamonas testosteroni i2 was isolated from activated sludge and found to be able to mineralize 3-chloroaniline (3-ca). during the mineralization, a yellow intermediate accumulated temporarily, due to the distal meta-cleavage of chlorocatechol. this strain was tested for its ability to clean wastewater containing 3-ca upon inoculation into activated sludge. to monitor its survival, the strain was chromosomally marked with the gfp gene and designated i2gfp. after inoculatio ... | 2000 | 10877785 |
| molecular analysis of surfactant-driven microbial population shifts in hydrocarbon-contaminated soil. | we analyzed the impact of surfactant addition on hydrocarbon mineralization kinetics and the associated population shifts of hydrocarbon-degrading microorganisms in soil. a mixture of radiolabeled hexadecane and phenanthrene was added to batch soil vessels. witconol sn70 (a nonionic, alcohol ethoxylate) was added in concentrations that bracketed the critical micelle concentration (cmc) in soil (cmc') (determined to be 13 mg g(-1)). addition of the surfactant at a concentration below the cmc' (2 ... | 2000 | 10877792 |
| variation among strains of xanthomonas campestris pv. vasculorum from mauritius and other countries based on fatty acid analysis. | fatty acid profiling was used to study variation amongst strains of xanthomonas campestris pv. vasculorum (xcv). they could be divided into five groups using cellular fatty acid profiles. group a strains represent a new and little known taxon and all came from plants of broom bamboo (thysanolaena maxima) from mauritius. group b strains included the xcv pathotype reference strain and were from palms, broom bamboo and sugarcane from mauritius, reunion and australia. group c contained southern afri ... | 2000 | 10879989 |
| cultivar-specific avirulence and virulence functions assigned to avrpphf in pseudomonas syringae pv. phaseolicola, the cause of bean halo-blight disease. | the avrpphf gene was cloned from pseudomonas syringae pathovar phaseolicola (pph:) races 5 and 7, based on its ability to confer avirulence towards bean cultivars carrying the r1 gene for halo-blight resistance, such as red mexican. avrpphf comprised two open reading frames, which were both required for function, and was located on a 154 kb plasmid (pav511) in pph: strain rw60 of pph:, lacking pav511, displayed a loss in virulence to a range of previously susceptible cultivars such as tendergree ... | 2000 | 10880434 |
| [major-polygene effect analysis of resistance to bacterial blight (xanthomonas campestris pv. oryzae) in rice]. | five crosses between resistance and susceptible were analyzed to study major-polygene effect using major-polygene mixed mode. the result showed that 3 of 5 crosses were controlled by both major gene and polygene. in addition, there were large variation of additive effect, variance as well as heredity of major gene polygene in 3 crosses. major gene was predominant in resistant variation, but durability should be considered. we suggested that construct major-polygene system be constructed in the l ... | 2000 | 10883537 |
| enhancement of induced disease resistance by simultaneous activation of salicylate- and jasmonate-dependent defense pathways in arabidopsis thaliana. | the plant-signaling molecules salicylic acid (sa) and jasmonic acid (ja) play an important role in induced disease resistance pathways. cross-talk between sa- and ja-dependent pathways can result in inhibition of ja-mediated defense responses. we investigated possible antagonistic interactions between the sa-dependent systemic acquired resistance (sar) pathway, which is induced upon pathogen infection, and the ja-dependent induced systemic resistance (isr) pathway, which is triggered by nonpatho ... | 2000 | 10890883 |
| sequence and molecular analysis of the rpoa cluster genes from xanthomonas campestris pv. campestris. | the xanthomonas campestris rpsm (s13)-rpsk (s11)-rpsd (s4)-rpoa (alpha)-rplq (l17) cluster, encoding rna polymerase alpha-subunit and four ribosomal proteins, reside in a 3164-bp dna region. the n-terminal sequence of the authentic alpha-protein determined chemically matches that predicted from the nucleotide sequence. rplq is monocistronic, instead of being co-transcribed with the other genes as in escherichia coli. antiserum against the his-tagged alpha-protein cross-reacted with the e. coli a ... | 2000 | 10899600 |
| requirement of the pseudomonas aeruginosa tonb gene for high-affinity iron acquisition and infection. | to investigate the contribution of the tonb protein to high-affinity iron acquisition in pseudomonas aeruginosa, we constructed tonb-inactivated mutants from strain pao1 and its derivative deficient in producing the siderophores pyoverdin and pyochelin. the tonb mutants could not grow in a free-iron-restricted medium prepared by apotransferrin addition, even though the medium was supplemented with each purified siderophore or with a heme source (hemoglobin or hemin). the tonb inactivation was sh ... | 2000 | 10899848 |
| role of phosphoglucomutase of bordetella bronchiseptica in lipopolysaccharide biosynthesis and virulence. | the phosphoglucomutase (pgm)-encoding gene of bordetella bronchiseptica is required for lipopolysaccharide (lps) biosynthesis. an insertion mutant of the wild-type b. bronchiseptica strain bb7865 which disrupted lps biosynthesis was created and characterized (bb7865pgm). genetic analysis of the mutated gene showed it shares high identity with pgm genes of various bacterial species and forms part of an operon which also encompasses the gene encoding phosphoglucose isomerase. functional assays for ... | 2000 | 10899872 |
| a protease-resistant catalase, kata, released upon cell lysis during stationary phase is essential for aerobic survival of a pseudomonas aeruginosa oxyr mutant at low cell densities. | a pseudomonas aeruginosa oxyr mutant was dramatically sensitive to h(2)o(2), despite possessing wild-type catalase activity. oxygen-dependent oxyr phenotypes also included an inability to survive aerobic serial dilution in luria broth and to resist aminoglycosides. plating the oxyr mutant after serial dilution in its own spent culture supernatant, which contained the major catalase kata, or under anaerobic conditions allowed for survival. kata was resistant to sodium dodecyl sulfate, proteinase ... | 2000 | 10913089 |
| novel insertion sequence elements associated with genetic heterogeneity and phenotype conversion in ralstonia solanacearum. | three insertion sequences (is) elements were isolated from the phytopathogen ralstonia solanacearum. southern hybridization using these is elements as probes revealed hybridization profiles that varied greatly between different strains of the pathogen. during a spontaneous phenotype conversion event, the promoter of the phca gene was interrupted by one of these is elements. | 2000 | 10913109 |
| effect of field inoculation with sinorhizobium meliloti l33 on the composition of bacterial communities in rhizospheres of a target plant (medicago sativa) and a non-target plant (chenopodium album)-linking of 16s rrna gene-based single-strand conformation polymorphism community profiles to the diversity of cultivated bacteria. | fourteen weeks after field release of luciferase gene-tagged sinorhizobium meliloti l33 in field plots seeded with medicago sativa, we found that the inoculant also occurred in bulk soil from noninoculated control plots. in rhizospheres of m. sativa plants, s. meliloti l33 could be detected in noninoculated plots 12 weeks after inoculation, indicating that growth in the rhizosphere preceded spread into bulk soil. to determine whether inoculation affected bacterial diversity, 1,119 bacteria were ... | 2000 | 10919821 |
| pseudomonas syringae hrp type iii secretion system and effector proteins. | pseudomonas syringae is a member of an important group of gram-negative bacterial pathogens of plants and animals that depend on a type iii secretion system to inject virulence effector proteins into host cells. in p. syringae, hrp/hrc genes encode the hrp (type iii secretion) system, and avirulence (avr) and hrp-dependent outer protein (hop) genes encode effector proteins. the hrp/hrc genes of p. syringae pv syringae 61, p. syringae pv syringae b728a, and p. syringae pv tomato dc3000 are flanke ... | 2000 | 10922033 |
| molecular and cell biology aspects of plague. | a 70-kb virulence plasmid (sometimes called pyv) enables yersinia spp. to survive and multiply in the lymphoid tissues of their host. it encodes the yop virulon, a system consisting of secreted proteins called yops and their dedicated type iii secretion apparatus called ysc. the ysc apparatus forms a channel composed of 29 proteins. of these, 10 have counterparts in almost every type iii system. secretion of some yops requires the assistance, in the bacterial cytosol, of small individual chapero ... | 2000 | 10922034 |
| genetic complexity of pathogen perception by plants: the example of rcr3, a tomato gene required specifically by cf-2. | genetic analysis of plant-pathogen interactions has demonstrated that resistance to infection is often determined by the interaction of dominant plant resistance (r) genes and dominant pathogen-encoded avirulence (avr) genes. it was postulated that r genes encode receptors for avr determinants. a large number of r genes and their cognate avr genes have now been analyzed at the molecular level. r gene loci are extremely polymorphic, particularly in sequences encoding amino acids of the leucine-ri ... | 2000 | 10922039 |
| parameters affecting gene expression from the pm promoter in gram-negative bacteria. | the pm promoter inserted chromosomally or in broad-host-range replicons based on plasmid rsf1010 or rk2 are useful systems for both high- and low-level expression of cloned genes in several gram-negative bacterial species. the positive pm regulator xyls is activated by certain substituted benzoic acid derivatives, and here we show that these effectors induce expression of pm at similar relative ranking levels in both escherichia coli and pseudomonas aeruginosa however, the kinetics of expression ... | 2000 | 10935724 |
| genomic and phenotypic characterization of xanthomonas cynarae sp. nov., a new species that causes bacterial bract spot of artichoke (cynara scolymus l.). | a bacterial disease of artichoke (cynara scolymus l.) was first observed in 1954 in brittany and the loire valley, france. this disease causes water-soaked spots on bracts and depreciates marketability of the harvest. ten strains of the pathogen causing bacterial spot of artichoke, previously identified as a member of the genus xanthomonas, were characterized and compared with type and pathotype strains of the 20 xanthomonas species using a polyphasic study including both phenotypic and genomic ... | 2000 | 10939652 |
| stationary-phase variation due to transposition of novel insertion elements in xanthomonas oryzae pv. oryzae. | xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. spontaneous mutants which are deficient for virulence and extracellular polysaccharide (eps) production accumulate in large numbers in stationary-phase cultures of this bacterium, a phenomenon which we have called stationary-phase variation. a clone (psd1) carrying the eps biosynthetic gene (gum) cluster of x. oryzae pv. oryzae restored eps production and virulence to several spv (for stationary-phase variatio ... | 2000 | 10940020 |
| evaluation of xanthomonas campestris survival in a soil microcosm system. | xanthomonas campestris pv. campestris is a pathogen of cruciferous plants. we studied the survival of the wild type strain and mutant derivatives which are deficient in exopolysaccharide (eps) or in extracellular protease synthesis in soil microcosms in order to test the hypothesis that, in this environment, adherence to soil particles and scavenging of nutrients are very important strategies for bacterial survival. in sterile soil microcosms, differences in survival were only observed between t ... | 1999 | 10943401 |
| bacterial quorum sensing in pathogenic relationships. | 2000 | 10948095 | |
| modified pyrogallol-initiated immunogold-silver enhancement technique applicable to prokaryotes. | a modified immunogold-silver enhancement technique that was designed to reduce the nonspecific granular background staining, particularly for application on prokaryotic organisms, is reported. aerial oxidation of pyrogallol contained in the commercial silver enhancer solution was effectively controlled during storage and in the reaction mixture. a combination of strategies such as storing the reagent under argon, modifying it using 0.5% (w/v) anhydrous sodium sulfite, reducing the concentration ... | 2000 | 10958966 |
| the redox-sensitive transcriptional activator oxyr regulates the peroxide response regulon in the obligate anaerobe bacteroides fragilis. | the peroxide response-inducible genes ahpcf, dps, and katb in the obligate anaerobe bacteroides fragilis are controlled by the redox-sensitive transcriptional activator oxyr. this is the first functional oxidative stress regulator identified and characterized in anaerobic bacteria. oxyr and dps were found to be divergently transcribed, with an overlap in their respective promoter regulatory regions. b. fragilis oxyr and dps proteins showed high identity to homologues from a closely related anaer ... | 2000 | 10960088 |
| characterization of the incw cryptic plasmid pxv2 from xanthomonas campestris pv. vesicatoria. | the gram-negative plant pathogen xanthomonas campestris pv. vesicatoria strain xv2 harbors an indigenous, cryptic plasmid pxv2 of 14.6 kb. this plasmid can only be maintained in xanthomonas and is incapable of self-transmission. however, incompatibility testing classified it in incw, a group containing the smallest number of naturally occurring, broad-host-range, conjugative plasmids. a pxv2 derivative containing only a 5.5-kb psti fragment is stably maintained. deletion of a 3.0-kb region from ... | 2000 | 10964626 |
| a serine protease-encoding gene (aprii) of alteromonas sp. strain o-7 is regulated by the iron uptake regulator (fur) protein. | the ferric uptake regulator (fur) box-like sequence was located upstream of the serine protease-encoding gene (aprii) from a marine bacterium, alteromonas sp. strain o-7. to clarify whether the production of aprii (the gene product of aprii) is regulated by the environmental iron concentrations, this strain was cultured under iron-depleted or iron-rich conditions and the level of aprii in the culture supernatant was analyzed by western blotting. the production of aprii was significantly represse ... | 2000 | 10966390 |
| starvation improves survival of bacteria introduced into activated sludge. | a phenol-degrading bacterium, ralstonia eutropha e2, was grown in luria-bertani (lb) medium or in an inorganic medium (called mp) supplemented with phenol and harvested at the late-exponential-growth phase. phenol-acclimated activated sludge was inoculated with the e2 cells immediately after harvest or after starvation in mp for 2 or 7 days. the densities of the e2 populations in the activated sludge were then monitored by quantitative pcr. the e2 cells grown on phenol and starved for 2 days (p- ... | 2000 | 10966407 |
| a novel gene encoding xanthan lyase of paenibacillus alginolyticus strain xl-1. | xanthan-modifying enzymes are powerful tools in studying structure-function relationships of this polysaccharide. one of these modifying enzymes is xanthan lyase, which removes the terminal side chain residue of xanthan. in this paper, the cloning and sequencing of the first xanthan lyase-encoding gene is described, i. e., the xala gene, encoding pyruvated mannose-specific xanthan lyase of paenibacillus alginolyticus xl-1. the xala gene encoded a 100, 823-da protein, including a 36-amino-acid si ... | 2000 | 10966413 |
| phylogenetic analysis of bacterial communities in mesophilic and thermophilic bioreactors treating pharmaceutical wastewater. | the phylogenetic diversity of the bacterial communities supported by a seven-stage, full-scale biological wastewater treatment plant was studied. these reactors were operated at both mesophilic (28 to 32 degrees c) and thermophilic (50 to 58 degrees c) temperatures. community fingerprint analysis by denaturing gradient gel electrophoresis (dgge) of the pcr-amplified v3 region of the 16s rrna gene from the domain bacteria revealed that these seven reactors supported three distinct microbial commu ... | 2000 | 10966414 |
| exposure of phytopathogenic xanthomonas spp. to lethal concentrations of multiple oxidants affects bacterial survival in a complex manner. | during plant-microbe interactions and in the environment, xanthomonas campestris pv. phaseoli is likely to be exposed to high concentrations of multiple oxidants. here, we show that simultaneous exposures of the bacteria to multiple oxidants affects cell survival in a complex manner. a superoxide generator (menadione) enhanced the lethal effect of an organic peroxide (tert-butyl hydroperoxide) by 1, 000-fold; conversely, treatment of cells with menadione plus h(2)o(2) resulted in 100-fold protec ... | 2000 | 10966423 |
| effect of oxygen on formation and structure of azotobacter vinelandii alginate and its role in protecting nitrogenase. | the activity of nitrogenase in the nitrogen-fixing bacterium azotobacter vinelandii grown diazotrophically under aerobic conditions is generally considered to be protected against o(2) by a high respiration rate. in this work, we have shown that a high rate of respiration is not the prevailing mechanism for nitrogenase protection in a. vinelandii grown in phosphate-limited nitrogen-free chemostat culture. instead, the formation of alginate appeared to play a decisive role in protecting the nitro ... | 2000 | 10966426 |
| dna-based diagnostic approaches for identification of burkholderia cepacia complex, burkholderia vietnamiensis, burkholderia multivorans, burkholderia stabilis, and burkholderia cepacia genomovars i and iii. | bacteria of the burkholderia cepacia complex consist of five discrete genomic species, including genomovars i and iii and three new species: burkholderia multivorans (formerly genomovar ii), burkholderia stabilis (formerly genomovar iv), and burkholderia vietnamiensis (formerly genomovar v). strains of all five genomovars are capable of causing opportunistic human infection, and microbiological identification of these closely related species is difficult. the 16s rrna gene (16s rdna) and reca ge ... | 2000 | 10970351 |
| bacteria in the leaf ecosystem with emphasis on pseudomonas syringae-a pathogen, ice nucleus, and epiphyte. | the extremely large number of leaves produced by terrestrial and aquatic plants provide habitats for colonization by a diversity of microorganisms. this review focuses on the bacterial component of leaf microbial communities, with emphasis on pseudomonas syringae-a species that participates in leaf ecosystems as a pathogen, ice nucleus, and epiphyte. among the diversity of bacteria that colonize leaves, none has received wider attention than p. syringae, as it gained notoriety for being the firs ... | 2000 | 10974129 |
| [xanthan production by xanthomonas campestris in a non-conventional culture medium]. | among 3 varieties of xanthomonas campestris, the variety ocumo (x. campestris pv. ocumo), showed the greatest capacity for producing xanthan. this bacteria grows appropriately and produces this polysaccharide in a wide diversity of carbohydrate sources. however, this strain does not produce xanthan when the carbohydrate comes from lignocellulosic materials. the glucose syrup favepro was the carbon source that showed the best yield (23 g/l) with the greatest viscosity (7000 cps) of xanthan. the o ... | 1999 | 10974710 |
| resistance of tomato and pepper to t3 strains of xanthomonas campestris pv. vesicatoria is specified by a plant-inducible avirulence gene. | tomato race 3 (t3) of xanthomonas campestris pv. vesicatoria (xcv) elicits a hypersensitive response (hr) in leaves of lycopersicon esculentum near-isogenic line (nil) 216 and pepper genotypes. one cosmid clone (35 kb) selected from a genomic library of a t3 strain induced an hr in all resistant plants. a 1.5-kb active subclone containing the putative avirulence (avr) gene, designated avrxv3, was sequenced. the avrxv3 gene encodes a 654-bp open reading frame (orf) with no homology to any known g ... | 2000 | 10975648 |
| in vitro antimicrobial properties of recombinant asabf, an antimicrobial peptide isolated from the nematode ascaris suum. | asabf is a csalphabeta-type antimicrobial peptide that contains four intramolecular disulfide bridges (y. kato and s. komatsu, j. biol. chem. 271:30493-30498, 1996). in the present study, a recombinant asabf was produced by using a yeast expression system, and its antimicrobial activity was characterized in detail. the recombinant asabf was active against all gram-positive bacteria tested (7 of 7; minimum bactericidal concentration [mbc], 0.03 to 1 microg/ml) except leuconostoc mesenteroides, so ... | 2000 | 10991847 |
| molecular and physiological analysis of an oxyr-regulated ahpc promoter in xanthomonas campestris pv. phaseoli. | in xanthomonas campestris pv. phaseoli, a gene for the alkyl hydroperoxide reductase subunit c (ahpc) had unique patterns of regulation by various forms of oxyr. reduced oxyr repressed expression of the gene, whereas oxidized oxyr activated its expression. this dual regulation of ahpc is unique and unlike all other oxyr-regulated genes. the ahpc transcription start site was determined. analysis of the region upstream of the site revealed promoter sequences that had high homology to the xanthomon ... | 2000 | 10998180 |
| identification of essential amino acids in the bacterial alpha -mannosyltransferase acea. | the alpha-mannosyltransferase acea from acetobacter xylinum belongs to the cazy family 4 of retaining glycosyltransferases. we have identified a series of either highly conserved or invariant residues that are found in all family 4 enzymes as well as other retaining glycosyltransferases. these residues included glu-287 and glu-295, which comprise an ex(7)e motif and have been proposed to be involved in catalysis. alanine replacements of each conserved residue were constructed by site-directed mu ... | 2000 | 11001941 |
| leafy gall formation is controlled by fasr, an arac-type regulatory gene in rhodococcus fascians. | rhodococcus fascians can interact with many plant species and induce the formation of either leafy galls or fasciations. to provoke symptoms, r. fascians strain d188 requires pathogenicity genes that are located on a linear plasmid, pfid188. the fas genes are essential for virulence and constitute an operon that encodes, among other functions, a cytokinin synthase gene. expression of the fas genes is induced by extracts of infected plant tissue only. we have isolated an arac-type regulatory gene ... | 2000 | 11004184 |
| identification of a copper-responsive two-component system on the chromosome of escherichia coli k-12. | using a genetic screen we have identified two chromosomal genes, cusrs (ylca ybcz), from escherichia coli k-12 that encode a two-component, signal transduction system that is responsive to copper ions. this regulatory system is required for copper-induced expression of pcoe, a plasmid-borne gene from the e. coli copper resistance operon pco. the closest homologs of cusr and cuss are plasmid-borne two-component systems that are also involved in metal responsive gene regulation: pcor and pcos from ... | 2000 | 11004187 |
| pcr assays that identify the grapevine dieback fungus eutypa lata. | eutypa lata is the causal fungal agent of eutypa dieback, a serious grapevine necrotic disease. the erratic and delayed (1 to 2 months) appearance of characteristic conidia on culture media and the presence of numerous microorganisms in decaying wood make it difficult either to identify or to detect e. lata in grapevine wood samples. we designed six pairs of pcr primers for diagnosis of e. lata. three primer pairs were derived from ribosomal dna internal transcribed spacer sequences, and three p ... | 2000 | 11010901 |
| pepper gene encoding a basic class ii chitinase is inducible by pathogen and ethephon. | a chitinase cdna clone (designated cachi2) was isolated from the cdna library of pepper leaves infected with xanthomonas campestris pv. vesicatoria. the 1004-bp full-length cachi2 cdna encodes a basic chitinase with an n-terminal 24 amino acid signal peptide followed by a catalytic region. an analysis of its sequence indicates that cachi2 is a class ii chitinase, because it does not have chitin-binding domain and c-terminal extension sequences. the deduced amino acid sequence of cachi2 has a hig ... | 2000 | 11011091 |
| pepper gene encoding a basic beta-1,3-glucanase is differentially expressed in pepper tissues upon pathogen infection and ethephon or methyl jasmonate treatment. | a basic beta-1,3-glucanase cdna clone (cabglu) was isolated from the cdna library constructed from hypersensitive response lesions of pepper leaves infected with avirulent strain of xanthomonas campestris pv. vesicatoria. the deduced polypeptide of cabglu which contains a c-terminal extension n-glycosylated at a single site characterized as typical structure of class i beta-1,3-glucanase has a high level of identity with tobacco basic beta-1,3-glucanase (77.4%), but only a moderate level of iden ... | 2000 | 11011097 |
| intracellular glucosaminidase of the bacterium xanthomonas campestris ibpm b-124: purification and properties. | a system of intracellular autolytic enzymes of the bacterium xanthomonas campestris ibpm b-124 was found to include enzymes with muramidase and glucosaminidase activities, while a system of extracellular bacteriolytic enzymes of the same bacterium includes muramidase, muramoylalanine amidase, and endopeptidase. using a purification technique including fractional precipitation with ammonium sulfate, gel-filtration on toyopearl hw-55f, and fplc ion-exchange chromatography on mono q, a preparation ... | 2000 | 11042495 |
| o-specific polysaccharide structure of the aqueous lipopolysaccharide fraction from xanthomonas campestris pv. vitians strain 1839. | the structure of xanthomonas campestris pv. vitians o-specific polysaccharide of the lipopolysaccharide fraction, extracted from the aqueous phase, was defined, on the basis of chemical and spectroscopical methods, as constituted by the following repeating unit: [--> 3)-alpha-l-rhap-(1 -->]n 3)-beta-l-rhap-(1 --> where n is more frequently equal to 2, but it also assumes values equal to 1 and to 3. | 2000 | 11072852 |
| s-adenosylmethionine decarboxylase from the archaeon methanococcus jannaschii: identification of a novel family of pyruvoyl enzymes. | polyamines are present in high concentrations in archaea, yet little is known about their synthesis, except by extrapolation from bacterial and eucaryal systems. s-adenosylmethionine (adomet) decarboxylase, a pyruvoyl group-containing enzyme that is required for spermidine biosynthesis, has been previously identified in eucarya and escherichia coli. despite spermidine concentrations in the methanococcales that are several times higher than in e. coli, no adomet decarboxylase gene was recognized ... | 2000 | 11073910 |
| a xanthomonas alkyl hydroperoxide reductase subunit c (ahpc) mutant showed an altered peroxide stress response and complex regulation of the compensatory response of peroxide detoxification enzymes. | alkyl hydroperoxide reductase subunit c (ahpc) is the catalytic subunit responsible for alkyl peroxide metabolism. a xanthomonas ahpc mutant was constructed. the mutant had increased sensitivity to organic peroxide killing, but was unexpectedly hyperresistant to h(2)o(2) killing. analysis of peroxide detoxification enzymes in this mutant revealed differential alteration in catalase activities in that its bifunctional catalase-peroxidase enzyme and major monofunctional catalase (kat1) increased s ... | 2000 | 11073935 |
| molecular signals required for type iii secretion and translocation of the xanthomonas campestris avrbs2 protein to pepper plants. | strains of xanthomonas campestris pv. vesicatoria (xcv) carrying avrbs2 are specifically recognized by bs2 pepper plants, resulting in localized cell death and plant resistance. agrobacterium-mediated transient expression of the xcv avrbs2 gene in plant cells results in bs2-dependent cell death, indicating that the avrbs2 protein alone is sufficient for the activation of disease resistance-mediated cell death in planta. we now provide evidence that avrbs2 is secreted from xcv and that secretion ... | 2000 | 11078519 |
| structure and sequence analysis of yersinia yada and moraxella uspas reveal a novel class of adhesins. | the non-fimbrial adhesins, yada of enteropathogenic yersinia species, and uspa1 and uspa2 of moraxella catarrhalis, are established pathogenicity factors. in electron micrographs, both surface proteins appear as distinct 'lollipop'-shaped structures forming a novel type of surface projection on the outer membranes. these structures, amino acid sequence analysis of these molecules and yada gene manipulation suggest a tripartite organization: an n-terminal oval head domain is followed by a putativ ... | 2000 | 11080146 |
| induced plant defense responses against chewing insects. ethylene signaling reduces resistance of arabidopsis against egyptian cotton worm but not diamondback moth. | the induction of plant defenses by insect feeding is regulated via multiple signaling cascades. one of them, ethylene signaling, increases susceptibility of arabidopsis to the generalist herbivore egyptian cotton worm (spodoptera littoralis; lepidoptera: noctuidae). the hookless1 mutation, which affects a downstream component of ethylene signaling, conferred resistance to egyptian cotton worm as compared with wild-type plants. likewise, ein2, a mutant in a central component of the ethylene signa ... | 2000 | 11080278 |
| improvement in bioreactor productivities using free radicals: hocl-induced overproduction of xanthan gum from xanthomonas campestris and its mechanism. | free-radical induction has been employed as a novel strategy to improve bioreactor productivity and, more specifically, the quality and productivity of xanthan gum from xanthomonas campestris cultures. a 210% increase in xanthan yield and a 20% increase in viscosity (quality) resulted from hocl (oxidant) treatment. the acetate mass fraction in xanthan gum decreased by 42% and its pyruvate mass fraction increased by 63% as a result of hocl treatment. the growth rate was almost unaffected by hocl ... | 2001 | 11084595 |
| a telomeric avirulence gene determines efficacy for the rice blast resistance gene pi-ta. | genetic mapping showed that the rice blast avirulence gene avr-pita is tightly linked to a telomere on chromosome 3 in the plant pathogenic fungus magnaporthe grisea. avr-pita corresponds in gene-for-gene fashion to the disease resistance (r) gene pi-ta. analysis of spontaneous avr-pita(-) mutants indicated that the gene is located in a telomeric 6.5-kb bglii restriction fragment. cloning and dna sequencing led to the identification of a candidate gene with features typical of metalloproteases. ... | 2000 | 11090206 |
| molecular evolution of virulence in natural field strains of xanthomonas campestris pv. vesicatoria. | the avrbs2 avirulence gene of the bacterial plant pathogen xanthomonas campestris pv. vesicatoria triggers disease resistance in pepper plants containing the bs2 resistance gene and contributes to bacterial virulence on susceptible host plants. we studied the effects of the pepper bs2 gene on the evolution of avrbs2 by characterizing the molecular basis for virulence of 20 x. campestris pv. vesicatoria field strains that were isolated from disease spots on previously resistant bs2 pepper plants. ... | 2000 | 11092868 |
| characterization of a major cluster of nif, fix, and associated genes in a sugarcane endophyte, acetobacter diazotrophicus. | a major 30.5-kb cluster of nif and associated genes of acetobacter diazotrophicus (syn. gluconacetobacter diazotrophicus), a nitrogen-fixing endophyte of sugarcane, was sequenced and analyzed. this cluster represents the largest assembly of contiguous nif-fix and associated genes so far characterized in any diazotrophic bacterial species. northern blots and promoter sequence analysis indicated that the genes are organized into eight transcriptional units. the overall arrangement of genes is most ... | 2000 | 11092875 |
| biological role of xanthomonadin pigments in xanthomonas campestris pv. campestris. | previous studies have indicated that the yellow pigments (xanthomonadins) produced by phytopathogenic xanthomonas bacteria are unimportant during pathogenesis but may be important for protection against photobiological damage. we used a xanthomonas campestris pv. campestris parent strain, single-site transposon insertion mutant strains, and chromosomally restored mutant strains to define the biological role of xanthomonadins. although xanthomonadin mutant strains were comparable to the parent st ... | 2000 | 11097878 |
| bacterial biodegradation of extractives and patterns of bordered pit membrane attack in pine wood. | wood extractives, commonly referred to as pitch, cause major problems in the manufacturing of pulp and paper. treatment of nonsterile southern yellow pine chips for 14 days with pseudomonas fluorescens, pseudomonas sp., xanthomonas campestris, and serratia marcescens reduced wood extractives by as much as 40%. control treatments receiving only water lost 11% of extractives due to the growth of naturally occurring microorganisms. control treatments were visually discolored after the 14-day incuba ... | 2000 | 11097890 |
| composition of soil microbial communities enriched on a mixture of aromatic hydrocarbons. | soil contaminated with c5+, which contained benzene (45%, wt/wt), dicyclopentadiene (dcpd) plus cyclopentadiene (together 20%), toluene (6%), styrene (3%), xylenes (2%), naphthalene (2%), and smaller quantities of other compounds, served as the source for isolation of 55 genomically distinct bacteria (standards). use of benzene as a substrate by these bacteria was most widespread (31 of 44 standards tested), followed by toluene (23 of 44), xylenes (14 of 44), styrene (10 of 44), and naphthalene ... | 2000 | 11097903 |
| functional tn5393-like transposon in the r plasmid pras2 from the fish pathogen aeromonas salmonicida subspecies salmonicida isolated in norway. | tn5393c containing stra-strb was identified as part of r plasmid pras2 from the fish pathogen aeromonas salmonicida subsp. salmonicida. this is the first time an intact and active transposon in the tn5393 family has been reported in an ecological niche other than an agricultural habitat. | 2000 | 11097945 |
| xv4-vrxv4: a new gene-for-gene interaction identified between xanthomonas campestris pv. vesicatoria race t3 and wild tomato relative lycopersicon pennellii. | strains of tomato race 3 (t3) of xanthomonas campestris pv. vesicatoria elicit a hypersensitive response (hr) in leaves of lycopersicon pennellii la716. genetic segregation of the resistance exhibited ratios near 3:1 in f2 populations, which confirmed that a single dominant gene controlled the inheritance of this trait. with the aid of a collection of introgression lines, restriction fragment length polymorphism, and cleaved amplified polymorphic sequence markers, the resistance locus was locate ... | 2000 | 11106027 |
| the chvh locus of agrobacterium encodes a homologue of an elongation factor involved in protein synthesis. | the virulence of agrobacterium tumefaciens depends on both chromosome- and ti plasmid-encoded gene products. in this study, we characterize a chromosomal locus, chvh, previously identified by tnphoa mutagenesis and shown to be required for tumor formation. through dna sequencing and comparison of the sequence with identified sequences in the database, we show that this locus encodes a protein similar in sequence to elongation factor p, a protein thought to be involved in peptide bond synthesis i ... | 2001 | 11114898 |
| hrpb2 and hrpf from xanthomonas are type iii-secreted proteins and essential for pathogenicity and recognition by the host plant. | the interaction between the plant pathogen xanthomonas campestris pv. vesicatoria and its host plants is controlled by hrp genes (hypersensitive reaction and pathogenicity), which encode a type iii protein secretion system. among type iii-secreted proteins are avirulence proteins, effectors involved in the induction of plant defence reactions. using non-polar mutants, we investigated the role of 12 hrp genes in the secretion of the avirulence protein avrbs3 from x. c. pv. vesicatoria and a heter ... | 2000 | 11115117 |
| xylella genomics and bacterial pathogenicity to plants. | xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. inspection of the sequence reveals high relatedness to many genes of other pathogens, notably xanthomonas campestris. based on this, we suggest that xylella possesses certain easily testable properties that contribute to pathogenicity. we also present some general considerations for deriving information on pathogenicity from bacterial genomics. | 2000 | 11119303 |
| detection of bacterial virulence genes by subtractive hybridization: identification of capsular polysaccharide of burkholderia pseudomallei as a major virulence determinant. | burkholderia pseudomallei, the etiologic agent of melioidosis, is responsible for a broad spectrum of illnesses in humans and animals particularly in southeast asia and northern australia, where it is endemic. burkholderia thailandensis is a nonpathogenic environmental organism closely related to b. pseudomallei. subtractive hybridization was carried out between these two species to identify genes encoding virulence determinants in b. pseudomallei. screening of the subtraction library revealed a ... | 2001 | 11119486 |
| a two-component system involving an hd-gyp domain protein links cell-cell signalling to pathogenicity gene expression in xanthomonas campestris. | the synthesis of extracellular enzymes and extracellular polysaccharide (eps) in xanthomonas campestris pv. campestris (xcc) is regulated by a cluster of genes called rpf (for regulation of pathogenicity factors). two of the genes, rpff and rpfb, have previously been implicated in the synthesis of a diffusible regulatory molecule, dsf. here, we describe a screen of transposon insertion mutants of xcc that identified two dsf-overproducing strains. in each mutant, the gene disrupted is rpfc, which ... | 2000 | 11123673 |
| structure of the o-specific polysaccharides of the lipopolysaccharides of xanthomonas campestris pv. vignicola gspb 2795 and gspb 2796. | the o-specific polysaccharides of xanthomonas campestris pv. vignicola gspb 2795 and gspb 2796 were studied by sugar and methylation analyses, smith degradation, id, 2d 1h and 13c nmr spectroscopy. it was found that the polysaccharides are similar branched d-rhamnans lacking strict regularity, and their structures can be described as follows: [carbohydrate equation: see text] where rha(v) is present in a non-stoichiometric amount, which varies from strain to strain. | 2000 | 11125825 |
| relationship between glycolysis and exopolysaccharide biosynthesis in lactococcus lactis. | the relationships between glucose metabolism and exopolysaccharide (eps) production in a lactococcus lactis strain containing the eps gene cluster (eps(+)) and in nonproducer strain mg5267 (eps(-)) were characterized. the concentrations of relevant phosphorylated intermediates in eps and cell wall biosynthetic pathways or glycolysis were determined by (31)p nuclear magnetic resonance. the concentrations of two eps precursors, udp-glucose and udp-galactose, were significantly lower in the eps(+) ... | 2001 | 11133425 |
| direct cloning from enrichment cultures, a reliable strategy for isolation of complete operons and genes from microbial consortia. | enrichment cultures of microbial consortia enable the diverse metabolic and catabolic activities of these populations to be studied on a molecular level and to be explored as potential sources for biotechnology processes. we have used a combined approach of enrichment culture and direct cloning to construct cosmid libraries with large (>30-kb) inserts from microbial consortia. enrichment cultures were inoculated with samples from five environments, and high amounts of avidin were added to the cu ... | 2001 | 11133432 |
| pigment and virulence deficiencies associated with mutations in the aroe gene of xanthomonas oryzae pv. oryzae. | xanthomonadins are yellow, membrane-bound pigments produced by members of the genus xanthomonas. we identified an ethyl methanesulfonate-induced xanthomonas oryzae pv. oryzae mutant (bxo65) that is deficient for xanthomonadin production and virulence on rice, as well as auxotrophic for aromatic amino acids (pig(-) vir(-) aro(-)). reversion analysis indicated that these multiple phenotypes are due to a single mutation. a genomic library of the wild-type strain was used to isolate a 7.0-kb clone t ... | 2001 | 11133452 |
| pantoea agglomerans strain eh318 produces two antibiotics that inhibit erwinia amylovora in vitro. | pantoea agglomerans (synonym: erwinia herbicola) strain eh318 produces through antibiosis a complex zone of inhibited growth in an overlay seeded with erwinia amylovora, the causal agent of fire blight. this zone is caused by two antibiotics, named pantocin a and b. using a genomic library of eh318, two cosmids, pcpp702 and pcpp704, were identified that conferred on escherichia coli the ability to inhibit growth of e. amylovora. the two cosmids conferred different antibiotic activities on e. col ... | 2001 | 11133457 |
| involvement of the xpsn protein in formation of the xpsl-xpsm complex in xanthomonas campestris pv. campestris type ii secretion apparatus. | the xps gene cluster is required for the second step of type ii protein secretion in xanthomonas campestris pv. campestris. deletion of the entire gene cluster caused accumulation of secreted proteins in the periplasm. by analyzing protein abundance in the chromosomal mutant strains, we observed mutual dependence for normal steady-state levels between the xpsl and the xpsm proteins. the xpsl protein was undetectable in total lysate prepared from the xpsm mutant strain, and vice versa. introducti ... | 2001 | 11133946 |
| genetic and physiological characterization of ohr, encoding a protein involved in organic hydroperoxide resistance in pseudomonas aeruginosa. | the ohr (organic hydroperoxide resistance) gene product of pseudomonas aeruginosa was essential for optimal resistance to organic hydroperoxides (ohps) but not to hydrogen peroxide or paraquat. a deltaohr mutant was hypersusceptible to ohps in disk inhibition assays and showed enhanced killing by ohps in liquid culture. the ohr gene product was demonstrated to contribute to the decomposition of ohps. transcription of ohr was induced up to 15-fold upon exposure to ohps, and this induction was ind ... | 2001 | 11133975 |
| hxc2, an arabidopsis mutant with an altered hypersensitive response to xanthomonas campestris pv. campestris. | a chemical mutagenized population of arabidopsis col-0-gl plants was screened for an altered hypersensitive response (hr) after spray inoculation with an hr-inducing isolate of xanthomonas campestris pv. campestris (strain 147). three classes of mutant were identified: those exhibiting an hr- phenotype or partial loss of hr; hyper-responsive mutants showing necrotic lesions rapidly leading to the collapse of leaves; and susceptible mutants. one mutant belonging to the susceptible class, hxc-2, w ... | 2000 | 11135109 |
| comparison of antifungal activities and 16s ribosomal dna sequences of clinical and environmental isolates of stenotrophomonas maltophilia. | in recent years, the gram-negative bacterium stenotrophomonas maltophilia has become increasingly important in biotechnology and as a nosocomial pathogen, giving rise to a need for new information about its taxonomy and epidemiology. to determine intraspecies diversity and whether strains can be distinguished based on the sources of their isolation, 50 s. maltophilia isolates from clinical and environmental sources, including strains of biotechnological interest, were investigated. the isolates ... | 2001 | 11136762 |
| oligoguluronates elicit an oxidative burst in the brown algal kelp laminaria digitata. | oligomeric degradation products of alginate elicited a respiratory and oxidative burst in the sporophytes of the kelp laminaria digitata. the generation of activated oxygen species (aos), o(2)(-), and h(2)o(2) was detected at the single cell level, using nitroblue tetrazolium precipitation and a redox-sensitive fluorescent probe, respectively. the oxidative burst involved diphenyleneiodonium-sensitive aos-generating machinery and its amplitude depended on the type of tissue. after a first elicit ... | 2001 | 11154336 |
| ion channel-forming alamethicin is a potent elicitor of volatile biosynthesis and tendril coiling. cross talk between jasmonate and salicylate signaling in lima bean. | alamethicin (ala), a voltage-gated, ion channel-forming peptide mixture from trichoderma viride, is a potent elicitor of the biosynthesis of volatile compounds in lima bean (phaseolus lunatus). unlike elicitation with jasmonic acid or herbivore damage, the blend of substances emitted comprises only the two homoterpenes, 4,11-dimethylnona-1,3,7-triene and 4,8,12-trimethyltrideca-1,3,7,11-tetraene, and methyl salicylate. inhibition of octadecanoid signaling by aristolochic acid and phenidone as we ... | 2001 | 11154344 |
| analysis of the type iv fimbrial-subunit gene fima of xanthomonas hyacinthi: application in pcr-mediated detection of yellow disease in hyacinths. | a sensitive and specific detection method was developed for xanthomonas hyacinthi; this method was based on amplification of a subsequence of the type iv fimbrial-subunit gene fima from strain s148. the fima gene was amplified by pcr with degenerate dna primers designed by using the n-terminal and c-terminal amino acid sequences of trypsin fragments of fima. the nucleotide sequence of fima was determined and compared with the nucleotide sequences coding for the fimbrial subunits in other type iv ... | 2001 | 11157222 |
| polysaccharide lyase: molecular cloning, sequencing, and overexpression of the xanthan lyase gene of bacillus sp. strain gl1. | when grown on xanthan as a carbon source, the bacterium bacillus sp. strain gl1 produces extracellular xanthan lyase (75 kda), catalyzing the first step of xanthan depolymerization (h. nankai, w. hashimoto, h. miki, s. kawai, and k. murata, appl. environ. microbiol. 65:2520-2526, 1999). a gene for the lyase was cloned, and its nucleotide sequence was determined. the gene contained an open reading frame consisting of 2,793 bp coding for a polypeptide with a molecular weight of 99,308. the polypep ... | 2001 | 11157235 |
| initiation of biofilm formation by pseudomonas aeruginosa 57rp correlates with emergence of hyperpiliated and highly adherent phenotypic variants deficient in swimming, swarming, and twitching motilities. | pseudomonas aeruginosa is a ubiquitous environmental bacterium capable of forming biofilms on surfaces as a survival strategy. it exhibits a large variety of competition/virulence factors, such as three types of motilities: flagellum-mediated swimming, flagellum-mediated swarming, and type iv pilus-mediated twitching. a strategy frequently used by bacteria to survive changing environmental conditions is to create a phenotypically heterogeneous population by a mechanism called phase variation. in ... | 2001 | 11157931 |
| identification and characterization of gsp65, an organic hydroperoxide resistance (ohr) gene encoding a general stress protein in enterococcus faecalis. | the enterococcus faecalis general stress protein gsp65 has been purified from two-dimensional gel electrophoresis. determination of its n-terminal sequence and characterization of the corresponding gene revealed that the gsp65 product is a 133-amino-acid protein sharing homologies with organic hydroperoxide resistance (ohr) proteins. transcriptional analysis of gsp65 gave evidence for a monocistronic mrna initiated 52 nucleotides upstream of the atg start codon and for an induction in response t ... | 2001 | 11157966 |
| catalase has a novel protective role against electrophile killing of xanthomonas. | the ability of xanthomonas: campestris pv. phaseoli to protect itself against lethal concentrations of man-made (n:-ethylmaleimide, nem) and endogenously produced (methylglyoxal, mg) electrophiles was investigated. pretreatment of x. c. pv. phaseoli with a low concentration of nem induced protection against lethal concentrations of nem and mg. mg pretreatment weakly induced protection against nem but not against mg itself. nem-induced protection against electrophile killing required new protein ... | 2001 | 11158366 |
| the insect endosymbiont sodalis glossinidius utilizes a type iii secretion system for cell invasion. | sodalis glossinidius is a maternally transmitted secondary endosymbiont residing intracellularly in tissues of the tsetse flies, glossina spp. in this study, we have used tn5 mutagenesis and a negative selection procedure to derive a s. glossinidius mutant that is incapable of invading insect cells in vitro and is aposymbiotic when microinjected into tsetse. this mutant strain harbors tn5 integrated into a chromosomal gene sharing high sequence identity with a type iii secretion system invasion ... | 2001 | 11172045 |
| from rags to riches: insights from the first genomic sequence of a plant pathogenic bacterium. | the recently published genomic sequence of xylella fastidiosa is the first for a free-living plant pathogen and provides clues to mechanisms of pathogenesis and survival in insect vectors. the sequence data should lead to improved control of this pathogen. | 2000 | 11178244 |
| molecular characterization and expression of the recx gene of xanthomonas campestris pv. citri. | two genes important in dna repair, reca and lexa, were recently identified in xanthomonas campestris pathovar citri (x.c. pv. citri). an open reading frame located immediately downstream of lexa and reca has now been isolated from this pathovar and characterized. this 486-bp open reading frame encodes a protein of 162 amino acids and shares substantial sequence similarity with recx of other bacterial species. the x.c. pv. citri recx protein was overexpressed in escherichia coli and purified; sds ... | 2001 | 11178726 |
| ethylene-dependent salicylic acid regulates an expanded cell death response to a plant pathogen. | the molecular events associated with susceptible plant responses to disease-causing organisms are not well understood. we have previously shown that ethylene-insensitive tomato plants infected with xanthomonas campestris pv. vesicatoria have greatly reduced disease symptoms relative to wild-type cultivars. here we show that salicylic acid (sa) is also an important component of the susceptible disease response. sa accumulates in infected wild-type tissues and is correlated with necrosis but does ... | 2001 | 11208023 |
| exchange of xcp (gsp) secretion machineries between pseudomonas aeruginosa and pseudomonas alcaligenes: species specificity unrelated to substrate recognition. | pseudomonas aeruginosa and pseudomonas alcaligenes are gram-negative bacteria that secrete proteins using the type ii or general secretory pathway, which requires at least 12 xcp gene products (xcpa and xcpp to -z). despite strong conservation of this secretion pathway, gram-negative bacteria usually cannot secrete exoproteins from other species. based on results obtained with erwinia, it has been proposed that the xcpp and/or xcpq homologs determine this secretion specificity (m. linderberg, g. ... | 2001 | 11208795 |
| the evolutionary history of chromosomal super-integrons provides an ancestry for multiresistant integrons. | integrons are genetic elements that acquire and exchange exogenous dna, known as gene cassettes, by a site-specific recombination mechanism. characterized gene cassettes consist of a target recombination sequence (attc site) usually associated with a single open reading frame coding for an antibiotic resistance determinant. the affiliation of multiresistant integrons (mris), which contain various combinations of antibiotic resistance gene cassettes, with transferable elements underlies the rapid ... | 2001 | 11209061 |
| structures of the o4 and o18 antigens of stenotrophomonas maltophilia: a case of enantiomeric repeating units. | the o-specific side-chain polymers of lipopolysaccharides from the reference strains for stenotrophomonas maltophilia serogroups 04 and o18 are both xylosylated rhamnans. in the 04 polymer, both sugar components are the d isomers, whereas the o18 polymer contains only the l isomers. by means of nmr spectroscopy, methylation analysis and smith degradation, the repeating unit of the 04 polymer was identified as a doubly-branched pentasaccharide of the structure shown below. the o18 polymer is base ... | 2001 | 11217974 |
| biological sensor for sucrose availability: relative sensitivities of various reporter genes. | a set of three sucrose-regulated transcriptional fusions was constructed. fusions p61rytir, p61rylac, and p61ryice contain the scrr sucrose repressor gene and the promoterless gfp, lacz, and inaz reporter genes, respectively, fused to the scry promoter from salmonella enterica serovar typhimurium. cells of erwinia herbicola containing these fusions are induced only in media amended with sucrose, fructose, or sorbose. while a large variation in sucrose-dependent reporter gene activity was observe ... | 2001 | 11229926 |
| salmonella host cell invasion emerged by acquisition of a mosaic of separate genetic elements, including salmonella pathogenicity island 1 (spi1), spi5, and sope2. | salmonella spp. possess a conserved type iii secretion system encoded within the pathogenicity island 1 (spi1; centisome 63), which mediates translocation of effector proteins into the host cell cytosol to trigger responses such as bacterial internalization. several translocated effector proteins are encoded in other regions of the salmonella chromosome. it remains unclear how this complex chromosomal arrangement of genes for the type iii apparatus and the effector proteins emerged and how the d ... | 2001 | 11244077 |
| agricultural microbes genome 2: first glimpses into the genomes of plant-associated microbes. | 2001 | 11251088 |