Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| toward an integrated linkage map of common bean. iii. mapping genetic factors controlling host-bacteria interactions. | restriction fragment length polymorphism (rflp)-based genetic linkage maps allow us to dissect the genetic control of quantitative traits (qt) by locating individual quantitative trait loci (qtls) on the linkage map and determining their type of gene action and the magnitude of their contribution to the phenotype of the qt. we have performed such an analysis for two traits in common bean, involving interactions between the plant host and bacteria, namely rhizobium nodule number (nn) and resistan ... | 1993 | 8514141 |
| xanthomonas campestris pv. parthenii pathovar nov. incitant of leaf blight of parthenium. | a new bacterial leaf blight disease of parthenium (parthenium hysterophorus l.) is described for the first time. the disease-causing bacterium was isolated and its morphological, physiological and biochemical characters were determined. the pathogenicity of bacterium is apparently limited only to parthenium. the pathogen was identified as xanthomonas campestris pv. parthenii pathovar nov. on the basis of morphological, physiological, biochemical and pathogenic characteristics. | 1995 | 8546453 |
| a region of the filamentous phage phi lf genome that can support autonomous replication and miniphage production. | a 2028-bp fragment from the rf dna of phi lf, a filamentous phage of xanthomonas campestris pv. campestris, was maintained autonomously as a minireplicon. upon superinfection of the cells harboring the minireplicon with phi lf, transducing miniphage particles were released. the minireplicon contained an open reading frame (orf346) able to encode a polypeptide of mw39144, which possessed consensus motifs found in the rep proteins from various sources. these findings suggested orf346 to be the gen ... | 1996 | 8573116 |
| expression and localization of hrpa1, a protein of xanthomonas campestris pv. vesicatoria essential for pathogenicity and induction ofthe hypersensitive reaction. | the hrp cluster of the pepper and tomato pathogen xanthomonas campestris pv. vesicatoria is required for both pathogenicity on susceptible host plants and induction of the hypersensitive reaction on resistant plants. the hrpa locus is located at the left end of the 25-kb hrp region and encodes a single 64-kda hrp protein, hrpa1, which belongs to the puld superfamily of proteins involved in type ii and type iii protein secretion. in this study, we developed a defined medium without any plant-deri ... | 1996 | 8576039 |
| xpsd, an outer membrane protein required for protein secretion by xanthomonas campestris pv. campestris, forms a multimer. | xpsd is an outer membrane lipoprotein, required for the secretion of extracellular enzymes by xanthomonas campestris pv. campestris. our previous studies indicated that when the xpsd gene was interrupted by transposon tn5, extracellular enzymes were accumulated in the periplasm (hu, n.-t., hung, m.-n., chiou, s.-j., tang, f., chiang, d.-c. huang, h.-y. and wu, c.-y. (1992) j. bacteriol. 174, 2679-2687). in this study, we constructed a series of substitutions and deletion mutant xpsd genes to inv ... | 1996 | 8576244 |
| [isolation of xanthan from xanthomonas campesteris b-1459 in mechanically agitated fermentors]. | xanthan production from xanthomonas campestris was studied by a mechanically shaken fermentor. influence of glucose concentration, aeration of culture media, rheology of broths and ph control was evaluated. different aeration conditions based on variation of stirring rates were assayed. substrate concentration was determined according to the miller method, and polymer production was performed by the cadmus method. the higher xanthan levels (i.e. 2.3%) were obtained at 750 rpm, with 1 v/v. min. i ... | 1995 | 8588053 |
| [kinetic model of micro-organism growth: the case of xanthomonas campestris]. | microbial growth is studied and kinetic models to describe the process rate useful in the scale-up are proposed. the growth of xanthomonas campestris nrrl b-1459, a bacterium producing xanthan, a major industrial gum, is studied. experimental data are arranged by means of different methods, and linear and non-linear regression techniques are applied in several ways (i.e. fixing or not fixing the values of certain parameters) and they are compared. to obtain parameter values with statistical mean ... | 1995 | 8588843 |
| cloning of a pectate lyase gene from xanthomonas campestris pv. malvacearum and comparison of its sequence relationship with pel genes of soft-rot erwinia and pseudomonas. | the cotton blight pathogen, xanthomonas campestris pv. malvacearum strain b414, produces an extracellular pectate lyase (pel) with an estimated m(r) of 41,000 and pi of 9.7. the gene coding for this enzyme initially identified in a 1.8-kb psti genomic dna fragment was cloned. the nucleotide sequences of this 1.8-kb fragment and two pel genes previously cloned from pseudomonas fluorescens and p. viridiflava were determined. these pel genes encoded pre-pel proteins consisting of 377 to 380 amino a ... | 1996 | 8589419 |
| a conformational model for cyclic beta-(1-->2)-linked glucans based on nmr analysis of the beta-glucans produced by xanthomonas campestris. | a cyclic hexadecaglucoside containing 15 beta-(1-->2)-linkages and one alpha-(1-->6)-linkage (a. amemura and j. cabrera-crespo, j. gen. microbiol. 132 (1986) 2443-2452) was purified from cultures of xanthomonas campestris. the homogeneity of this glucan preparation facilitated the complete assignment of its 1h nmr spectrum and the assignment of all of the c-1 and c-2 resonances in its 13c nmr spectrum to specific residues within the glucan. the resonances (i.e., h-1, h-2, c-1 and c-2) that are c ... | 1995 | 8590443 |
| isolation and characterization of the reca gene of xanthomonas campestris pv. campestris. | a 1.8-kb nsii-stui fragment containing the reca gene of xanthomonas campestris pv. campestris was cloned by a pcr-based approach and complementation of escherichia coli hb 101. sequence analysis of this fragment revealed an orf (orf343) of 1,032 bp able to encode a protein of 343 amino acids with a calculated mw of 37,021 da, a size similar to the values detected by in vitro system and western blotting. it showed 69.6% identity to the e. coli reca in amino acid sequence. amino acid residues of t ... | 1996 | 8619877 |
| linkage of genes essential for synthesis of a polysaccharide capsule in sphingomonas strain s88. | several structurally related capsular polysaccharides that are secreted by members of the genus sphingomonas are being developed as aqueous rheological control agents for diverse industrial and food applications. they include gellan (s-60), welan (s-130), rhamsan (s-194), s-657, s-88, s-198, s-7, and nw-11. we refer to these polysaccharides as sphingans, after the genus name. this paper characterizes the first gene cluster isolated from a sphingomonas species (s88) that is required for capsule s ... | 1996 | 8626338 |
| cell-associated glucans of burkholderia solanacearum and xanthomonas campestris pv. citri: a new family of periplasmic glucans. | the cell-associated glucans produced by burkholderia solanacearum and xanthomonas campestris pv. citri were isolated by trichloroacetic acid treatment and gel permeation chromatography. the compounds obtained were characterized by compositional analysis, matrix-assisted laser desorption ionization mass spectrometry, and high-performance anion-exchange chromatography. b. solanacearum synthesizes only a neutral cyclic glucan containing 13 glucose residues, and x. campestris pv. citri synthesizes a ... | 1996 | 8636027 |
| genomic localization of tomato genes that control a hypersensitive reaction to xanthomonas campestris pv. vesicatoria (doidge) dye. | xanthomonas campestris pv. vesicatoria causes bacterial spot, one of the most serious diseases of tomatoes. the lycopersicon esculentum accession 'hawaii 7998' is the only reliable source of resistance to race 1 strains of the pathogen. this resistance is associated with a hypersensitive reaction controlled by multiple nondominant genes. the inoculated area becomes fully necrotic 24 hr after inoculation in 'hawaii 7998,' whereas full necrosis is observed 5 and 4 days after inoculation in the sus ... | 1995 | 8647402 |
| hrpxv, an arac-type regulator, activates expression of five of the six loci in the hrp cluster of xanthomonas campestris pv. vesicatoria. | hrp genes, basic pathogenicity genes of the pepper and tomato pathogen xanthomonas campestris pv. vesicatoria, are regulated dependent on environmental conditions. we isolated the hrpxv gene, which was found to be outside the large hrp cluster comprising the six loci hrpa to hrpf. the predicted hrpxv protein is 476 amino acids long and has a molecular mass of 52.5 kda. hrpx is highly conserved among xanthomonads and is a member of the arac family of regulatory proteins. an hrpxv insertion mutant ... | 1996 | 8655542 |
| sequence and expression analysis of the hrpb pathogenicity operon of xanthomonas campestris pv. vesicatoria which encodes eight proteins with similarity to components of the hrp, ysc, spa, and fli secretion systems. | in this paper we describe the molecular characterization of hrpb, the largest operon in the xanthomonas campestris pv. vesicatoria hrp cluster. the hrpb region encompasses 6 kb and encodes eight putative proteins, seven of which were expressed in escherichia coli. the hrpb3 protein is the only one carrying a signal peptide sequence at the n-terminus and is a putative lipoprotein localized in the outer membrane of x. campestris pv. vesicatoria. the hrpb4 and hrpb8 proteins contain one and five pu ... | 1995 | 8664494 |
| cloning of extracellular lipase gene from xanthomonas campestris pathovar sesami on to escherichia coli. | a lipase gene from x. campestris pv. sesami (strain xcs 1) causal agent of leaf spot disease of sesamum indicum, was cloned onto e. colt. xcs showed the presence of lip+ transformants on dye's medium with 1% glycerol as sole carbon source. the recombinant plasmids were isolated and when digested with eco r1, yielded 2 fragments with molecular weights 4.0 and 4.8 kb. thus a 8.8 kb insert dna fragment was obtained which showed lipase activity. | 1996 | 8698403 |
| expression of periplasmic alpha-amylase of xanthomonas campestris k-11151 in escherichia coli and its action on maltose. | a gene encoding the periplasmic alpha-amylase of xanthomonas campestris k-11151 was cloned into escherichia coli using puc19 as a vector. an orf of 1578 bp was deduced to be the amylase structural gene. the primary structure of the enzyme had little identity with other alpha-amylases, except with the enzyme from bacillus megaterium. the enzyme was expressed in e. coli from the lac promoter of puc19 and was found to be transported to the periplasmic space. the expressed enzyme showed the same the ... | 1996 | 8704990 |
| spontaneous and induced mutations in a single open reading frame alter both virulence and avirulence in xanthomonas campestris pv. vesicatoria avrbs2. | molecular characterization of the avrbs2 locus from xanthomonas campestris pv. vesicatoria has revealed that expression of this gene triggers disease resistance in bs2 pepper (capsicum annuum) plants and contributes to virulence of the pathogen. deletion analysis and site-directed mutagenesis established the avrbs2 gene as a 2,190-bp open reading frame encoding a putative 80.1-kda protein. two classes of xanthomonas pathogens evading bs2 host resistance and displaying reduced fitness were found ... | 1996 | 8755898 |
| isolation and nucleotide sequence of the gdp-mannose:cellobiosyl-diphosphopolyprenol alpha-mannosyltransferase gene from acetobacter xylinum. | a genetic locus from acetobacter xylinum involved in acetan polysaccharide synthesis has been characterized. the chromosomal region was identified by screening a genomic library of a. xylinum in a xanthomonas campestris mutant defective in xanthan polysaccharide synthesis. the a. xylinum cosmid clone can functionally complement a xanthan-negative mutant. the polymer produced by the recombinant strain was found to be indistinguishable from xanthan. insertion mutagenesis and subcloning of the cosm ... | 1996 | 8759843 |
| promoter analysis of the xanthomonas campestris pv. campestris gum operon directing biosynthesis of the xanthan polysaccharide. | the xanthomonas campestris gum gene cluster is composed of 12 genes designated gumb, -c, -d, -e, -f, -g, -h, -i, -j, -k, -l, and -m. the transcriptional organization of this gene cluster was analyzed by the construction of gum-lacz transcriptional fusions in association with plasmid integration mutagenesis. this analysis, coupled with primer extension assays, indicated that the gum region was mainly expressed as an operon from a promoter located upstream of the first gene, gumb. | 1996 | 8763965 |
| two cold-inducible genes encoding lipid transfer protein ltp4 from barley show differential responses to bacterial pathogens. | the barley genes hvltp4.2 and hvltp4.3 both encode the lipid transfer protein ltp4 and are less than 1 kb apart in tail-to-tail orientation. they differ in their non-coding regions from each other and from the gene corresponding to a previously reported ltp4 cdna (now ltp4.1). southern blot analysis indicated the existence of three or more ltp4 genes per haploid genome and showed considerable polymorphism among barley cultivars. we have investigated the transient expression of genes hvltp4.2 and ... | 1996 | 8804389 |
| a gene for superoxide dismutase from xanthomonas campestris pv. campestris and its expression during bacterial-plant interactions. | a recombinant plasmid selected from a library of xanthomonas campestris pv. campestris genomic dna by functional complementation of a superoxide dismutase (sod)-deficient strain of escherichia coli contained a gene encoding the major sod activity of x. campestris pv. campestris. inhibition and renaturation studies suggested that manganese was the metal cofactor for this sod. examination of the nucleotide sequence of an active subclone revealed a 612-bp open reading frame that encodes a protein w ... | 1996 | 8810073 |
| cloning and characterization of the rpfc gene of xanthomonas oryzae pv. oryzae: involvement in exopolysaccharide production and virulence to rice. | rpfc is one of a cluster of genes which coordinately regulate the synthesis of extracellular enzymes and exopolysaccharide and pathogenicity in xanthomonas campestris pv. campestris, the black rot pathogen of brassicas. an rpfc homolog which could functionally complement an rpfc mutant of x. campestris pv. campestris was identified in xanthomonas oryzae pv. oryzae and the gene was characterized. mutation of this gene in x. oryzae pv. oryzae had no effect on extracellular enzymes, but exopolysacc ... | 1996 | 8810082 |
| the type iv pre-pilin leader peptidase of xanthomonas campestris pv. campestris is functional without conserved cysteine residues. | type iv pre-pilin leader peptidase was demonstrated to be required for protein secretion, in addition to its involvement in biogenesis of type iv piii. the type iv pre-pilin leader peptidase gene of xanthomonas campestris pv. campestris was located on a 3 kb accl fragment on account of its hybridization with the dna fragment containing the type iv pre-pilin leader-peptidase gene pild/xcpa of pseudomonas aeruginosa. sequencing of the cloned fragment revealed an open reading frame (orf) (designate ... | 1995 | 8817497 |
| the gene encoding udp-glucose pyrophosphorylase is required for the synthesis of xanthan gum in xanthomonas campestris. | xanthomonas campestris pv. campestris produces a large quantity of exopolysaccharide, xanthan gum, rendering the colonies mucoid. g76e was a non-mucoid mutant isolated from xc17 by tn5 mutagenesis. a 3.0-kb kpni-ecori fragment from the xc17 chromosome was able to restore mucoid phenotype to g76e. sequence analysis of the region responsible for the restoration revealed an open reading frame, orf324, able to encode a polypeptide of 35,232 da which shows striking similarity to the udp-glucose pyrop ... | 1996 | 8831665 |
| genetic analysis of the transcriptional arrangement of azotobacter vinelandii alginate biosynthetic genes: identification of two independent promoters. | the study of alginate biosynthesis, the exopolysaccharide produced by azotobacter vinelandii and pseudomonas aeruginosa, might lead to different biotechnological applications. here we report the cloning of a. vinelandii alga, the gene coding for the bifunctional enzyme phosphomannose isomerase-guanosine diphospho-o-mannose pyrophosphorylase (pmi-gmp). this gene was selected by the complementation for xanthan gum production of xanthomonas campestris pv. campestris xanb-mutants, which lack this en ... | 1996 | 8866469 |
| hrpg, a key hrp regulatory protein of xanthomonas campestris pv. vesicatoria is homologous to two-component response regulators. | xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease of pepper and tomato plants. expression of its basic pathogenicity genes, the hrp genes, is induced in planta and in xvm2 medium and is dependent on the hrp regulatory gene hrpxv for five out of six loci in the 23-kb hrp cluster. here we describe the isolation of a novel hrp gene, hrpg, that was identified after chemical mutagenesis and that is located next to the hrpxv gene. in a hrpg mutant induction of expres ... | 1996 | 8870269 |
| isolation and characterization of the gene encoding an aminopeptidase involved in the selective toxicity of ascamycin toward xanthomonas campestris pv. citri. | an aminopeptidase gene named xap has been isolated from xanthomonas campestris pv. citri, a plant pathogenic bacterium. the bacterium is one of the rare micro-organisms susceptible to ascamycin, an aminoacyl nucleoside antibiotic that inhibits protein synthesis. sequence analysis reveals that the gene encodes a 311 amino acid protein with a calculated molecular mass of 35134 da and approx. 50% identity for amino acids to the proline iminopeptidase from neisseria gonorrhoeae. the xap gene product ... | 1996 | 8870654 |
| proline iminopeptidase gene from xanthomonas campestris pv. citri. | the pip gene coding for the proline iminopeptidase (pip) of xanthomonas campestris pv. citri was cloned in an escherichia coli leub strain using a selective medium containing the dipeptide d-ala-l-leu as the sole source of l-leucine. nucleotide sequencing of this gene revealed a 939 bp open reading frame encoding a 312 amino acid protein (35 126 da). the deduced amino acid sequence showed 47% identity with the pip from neisseria gonorrhoeae. a lacz-pip fusion gene was overexpressed in e. coli un ... | 1996 | 8885412 |
| identification and nucleotide sequence of rhizobium meliloti insertion sequence isrm6, a small transposable element that belongs to the is3 family. | the insertion sequence isrm6 is a small transposable element identified in rhizobium meliloti strain gr4 by sequence analysis. two copies of this is element were found in strain gr4, one of them is linked to the nfe genes located on plasmid prmegr4b. isrm6 seems to be widespread in r. meliloti. data suggest that isrm6 is active in transposition at an estimated frequency of 2 x 10(-5) per generation per cell in strain gr4. this 1269-bp element carries 27/26-bp terminal imperfect inverted repeats ... | 1996 | 8917074 |
| the ori of filamentous phage phi lf is located within the gene encoding the replication initiation protein. | phi lf is a filamentous phage of xanthomonas campestris pv. campestris. in this study, the origin for phi lf replication was located in a 121-bp taqi fragment within gii, the gene encoding the replication initiation protein. this fragment, ligating with a gmr catridge, was able to be maintained as a plasmid (pt2) in strain xc17 with the gii being provided in trans. ssdna of pt2 was detected in the cells, indicating that pt2 may replicate by a rolling circle replication mechanism. upon superinfec ... | 1996 | 8920901 |
| construction of a broad-host-range promoter-probing vector and cloning of promoter fragments of xanthomonas campestris. | a broad-host-range promoter-probing vector, pmy3 (8.0 kb), was constructed for cloning of dna fragments containing promoter sequences of xanthomonas campestris pv. campestris. this vector (pmy3) consists of the rk2 replicon, promoterless luxab genes, the thr attenuator to block the transcription of rna into the luxab region, and multiple cloning sites for cloning of the fragment carrying promoter sequences. the feasibility of using pmy3 as a promoter-probing vector in both e. coli and xc17 was d ... | 1996 | 8920924 |
| identification, cloning and sequencing the acea gene involved in acetan biosynthesis in acetobacter xylinum. | the acea gene from acetobacter xylinum was identified and cloned from a genomic dna library. the complete dna sequence was determined and computer analysis of the translated gene sequence revealed homology with the deduced amino acid sequence of gumd from xanthomonas campestris. therefore acea is likely to encode the phosphate-prenyl glucose l-phosphate transferase catalyzing the first step in acetan biosynthesis in a. xylinum. | 1996 | 8935665 |
| single-stranded dna binding protein from bacteriophage cf: characterization, gene localization and protein-ssdna complex. | the single-stranded dna binding protein from the filamentous bacteriophage cf has been purified and characterized. the first 12 amino acids, resulting from the n-terminal amino acid sequencing analysis of the protein, agree with an open reading frame (orf) on the cf genome. the orf contains 294 bp and codes for a 98 a.a. protein of molecular weight 10.8 kda, consistent with the result from the denaturing protein gel analysis. the protein appears to be a homodimer as evident from the apparent mol ... | 1996 | 8950189 |
| regulation of the oxidative stress protective enzymes, catalase and superoxide dismutase in xanthomonas--a review. | xanthomonas showed atypical regulation of catalase (kat) and superoxide dismutase with respect to growth phase and response to various inducers. the highest levels of both enzymes were detected during early log phase of growth and declined as growth continued. this was in contrast to resistance levels to superoxides, h2o2 and organic peroxides, which reached maximum levels during stationary phase. xanthomonas catalase was induced over six fold by superoxide generators and methyl methane sulfonat ... | 1996 | 8955626 |
| the rpon gene of xanthomonas campestris pv. vesicatoria is not required for pathogenicity. | we have cloned the rpon region of the pepper and tomato pathogen xanthomonas campestris pv. vesicatoria to analyze its role in pathogenicity and hrp gene activation. open reading frame 3 (orf3) from this region is predicted to encode a protein that is up to 45% identical and 65% similar to previously described rpon proteins and was shown to be essential for the utilization of nitrate as sole nitrogen source. the x. campestris pv. vesicatoria rpon gene is, however, not required for pathogenicity ... | 1996 | 8969534 |
| recognition of the bacterial avirulence protein avrbs3 occurs inside the host plant cell. | the molecular mechanism by which bacterial avirulence genes mediate recognition by resistant host plants has been enigmatic for more than a decade. in this paper we provide evidence that the xanthomonas campestris pv. vesicatoria avirulence protein avrbs3 is recognized inside the plant cell. transient expression of avrbs3 in pepper leaves, using agrobacterium tumefaciens for gene delivery, results in hypersensitive cell death, specifically on plants carrying the resistance gene bs3. in addition, ... | 1996 | 8980236 |
| genetic analysis of the acetan biosynthetic pathway in acetobacter xylinum: nucleotide sequence analysis of the aceb, acec, aced and acee genes. | sequence analysis of a 5.323 kb chromosomal dna fragment from acetobacter xylinum involved in the biosynthesis of the exopolysaccharide acetan, revealed the presence of four ace genes designated aceb, acec, aced and acee. comparison of translated gene sequences to the databanks was used to assign putative gene functions. aceb displayed strong homology to a glucose-diphosphoprenyl beta, d-glucose transferase from xanthomonas campestris, while acec was homologous to a cellobiosyl-diphosphoprenyl a ... | 1996 | 8988363 |
| pigb determines a diffusible factor needed for extracellular polysaccharide slime and xanthomonadin production in xanthomonas campestris pv. campestris. | seven xanthomonadin transcriptional units (piga through pigg) were identified by transposon saturation mutagenesis within an 18.6-kbp portion of the previously identified 25.4-kbp pig region from xanthomonas campestris pv. campestris (strain b-24). since marker exchange mutant strains with insertions in one 3.7-kbp portion of pig could not be obtained, mutations in this region may be lethal to the bacterium. complementation analyses with different insertion mutations further defined and confirme ... | 1997 | 8990296 |
| crystallization and preliminary x-ray diffraction analysis of proline iminopeptidase from xanthomonas campestris pv. citri. | proline iminopeptidase from xanthomonas campestris pv. citri, displaying no significant sequence homology to any protein previously analyzed by x-ray crystallography, has been crystallized using the vapour diffusion method. two different orthorhombic crystal forms (space group c222 and i222) were obtained from a solution containing nacl or polyethylene glycol monomethyl ether (mw 5000) as precipitating agent for the native and lanthanum-derivatized protein, respectively. complete diffraction dat ... | 1997 | 9000519 |
| catabolite-repressor-like protein regulates the expression of a gene under the control of the escherichia coli lac promoter in the plant pathogen xanthomonas campestris pv. campestris. | xanthomonas campestris pv. campestris, the causal agent of black-rot disease of cruciferous plants, and an important industrial microbe, was able to express the escherichia coli beta-glucuronidase reporter gene (uida) when fused to the e. coli lactose operon promoter on a wide-host-range plasmid vector. the gene fusion is expressed constitutively at high levels in both complex and defined media using a wide range of carbon sources, and is not repressible by glucose or inducible by the gratuitous ... | 1996 | 9008890 |
| rapid induction by wounding and bacterial infection of an s gene family receptor-like kinase gene in brassica oleracea. | a receptor-like kinase, srk, has been implicated in the autoincompatible response that leads to the rejection of self-pollen in brassica plants. srk is encoded by one member of a multigene family, which includes several receptor-like kinase genes with patterns of expression very different from that of srk but of unknown function. here, we report the characterization of a novel member of the brassica s gene family, sfr2. rna gel blot analysis demonstrated that sfr2 mrna accumulated rapidly in res ... | 1997 | 9014364 |
| characterization of the fima gene encoding bundle-forming fimbriae of the plant pathogen xanthomonas campestris pv. vesicatoria. | the fima gene of xanthomonas campestris pv. vesicatoria was identified and characterized. a 20-mer degenerate oligonucleotide complementary to the n-terminal amino acid sequence of the purified 15.5-kda fimbrillin was used to locate fima on a 2.6-kb sali fragment of the x. campestris pv. vesicatoria 3240 genome. the nucleotide sequence of a 1.4-kb fragment containing the fima region revealed two open reading frames predicting highly homologous proteins fima and fimb. fima, which was composed of ... | 1997 | 9023213 |
| construction and use of a versatile set of broad-host-range cloning and expression vectors based on the rk2 replicon. | the plasmid vectors described in this report are derived from the broad-host-range rk2 replicon and can be maintained in many gram-negative bacterial species. the complete nucleotide sequences of all of the cloning and expression vectors are known. important characteristics of the cloning vectors are as follows: a size range of 4.8 to 7.1 kb, unique cloning sites, different antibiotic resistance markers for selection of plasmid-containing cells, orit-mediated conjugative plasmid transfer, plasmi ... | 1997 | 9023917 |
| the hrpa and hrpc operons of erwinia amylovora encode components of a type iii pathway that secretes harpin. | a 6.2-kb region of dna corresponding to complementation groups ii and iii of the erwinia amylovora hrp gene cluster was analyzed. transposon mutagenesis indicated that the two complementation groups are required for secretion of harpin, an elicitor of the hypersensitive reaction. the sequence of the region revealed 10 open reading frames in two putative transcription units: hrpa, hrpb, hrcj, hrpd, and hrpe in the hrpa operon (group iii) and hrpf, hrpg, hrcc, hrpt, and hrpv in the hrpc operon (gr ... | 1997 | 9045830 |
| rapid, transient, and highly localized induction of plastidial omega-3 fatty acid desaturase mrna at fungal infection sites in petroselinum crispum. | parsley (petroselinum crispum) plants and suspension-cultured cells have been used extensively for studies of non-host-resistance mechanisms in plant/pathogen interactions. we now show that treatment of cultured parsley cells with a defined peptide elicitor of fungal origin causes rapid and large changes in the levels of various unsaturated fatty acids. while linoleic acid decreased and linolenic acid increased steadily for several hours, comparatively sharp increases in oleic acid followed a bi ... | 1997 | 9050908 |
| sequence analysis of the small cryptic xanthomonas campestris pv. vesicatoria plasmid pxv64 encoding a rep protein similar to gene ii protein of phage 12-2. | the complete nucleotide sequence (1,851 bp) was determined for the xanthomonas campestris pv. vesicatoria plasmid pxv64. sequence analysis revealed an intergenic region (ig) of 355 bp and two oppositely running open reading frames, orf1 and orf2, encoding polypeptides of 39 and 16 kda, respectively. while the function of orf2 is not known, orf1 is suggested to be the gene encoding rep protein based on (i) similarity in amino acid sequence to that of the gene ii protein (giip) of filamentous phag ... | 1997 | 9070232 |
| is1473, a putative insertion sequence identified in the plasmid pao1 from arthrobacter nicotinovorans: isolation, characterization, and distribution among arthrobacter species. | a putative insertion sequence (is1473) has been cloned and sequenced. the 1087-bp element was found between the moaa and the ndha genes in the upstream region of the nicotine dehydrogenase (ndh) operon in the 160-kb pao1 plasmid of arthrobacter nicotinovorans. it is flanked by an imperfect repeat of 33 bp and carries two overlapping open reading frames which, by programmed -1 translational frameshifting, may produce a transposase of 36.735 da with a pi = 10. 18. the deduced protein is similar to ... | 1997 | 9073580 |
| hrp pilus: an hrp-dependent bacterial surface appendage produced by pseudomonas syringae pv. tomato dc3000. | hypersensitive response and pathogenicity (hrp) genes control the ability of major groups of plant pathogenic bacteria to elicit the hypersensitive response (hr) in resistant plants and to cause disease in susceptible plants. a number of hrp proteins share significant similarities with components of the type iii secretion apparatus and flagellar assembly apparatus in animal pathogenic bacteria. here we report that pseudomonas syringae pv. tomato strain dc3000 (race 0) produces a filamentous surf ... | 1997 | 9096416 |
| molecular cloning, characterization, and mutagenesis of a pel gene from pseudomonas syringae pv. lachyrmans encoding a member of the erwinia chrysanthemi pelade family of pectate lyases. | the pels gene from pseudomonas syringae pv. lachrymans 859 was cloned by heterologous expression in nonpectolytic p. syringae pv. syringae buvs1, using genomic dna libraries constructed with two novel broad-host-range cosmid vectors, pcpp34 and pcpp47. screening of p. syringae pv. syringae transconjugants for the ability to pit pectate media at ph 6.0 and 8.5 yielded several overlapping clones of the same dna region. ultrathin-layer isoelectric focusing gels, activity-stained with diagnostically ... | 1997 | 9100381 |
| identification of a pathogenicity locus, rpfa, in erwinia carotovora subsp. carotovora subsp. carotovora that encodes a two-component sensor-regulator protein. | a mutant of erwinia carotovora subsp. carotovora, ah2552, created by a mud1 insertion was found to be reduced in plant pathogenicity and deficient in extracellular protease and cellulase activity, although it produced normal levels of pectate lyase and polygalacturonase. a cosmid clone, pec462, was isolated from a wild-type e. carotovora subsp. carotovora dna library that concomitantly restored pathogenicity and protease and cellulase activities of ah2552 to wild-type levels when present in tran ... | 1997 | 9100385 |
| cloning, sequencing, and expression of the rpod gene encoding the primary sigma factor of xanthomonas campestris. | a dna fragment encoding the primary sigma factor from xanthomonas campestris pv. campestris was cloned and sequenced. the gene (rpod) encodes a polypeptide of 622 amino acids with a calculated mw of 70,700. the deduced amino acid sequence exhibits extensive sequence homology to the conserved regions of the primary sigma factors from bacteria. the gene product expressed in escherichia coli, detected by western blot analysis, had a mw similar to that estimated for the purified protein in sds-page. ... | 1997 | 9126341 |
| isolation and nucleotide sequence of the gene encoding the xami dna methyltransferase of xanthomonas campestris pv. amaranthicola. | the gene (xamim) encoding the dna methyltransferase of the xami restriction-modification system from xanthomonas campestris pv. amaranithicola (m.xami) has been cloned in escherichia coli and its nucleotide sequence determined. the sequence predicts a protein of 527 amino acids that contains nine conserved motifs characteristic of dna amino methyltransferases. in fact, m.xami shows significant similarity with n6-adenine methyltransferases of the gamma group of amino methyltransferases, including ... | 1997 | 9130589 |
| the a protein of the filamentous bacteriophage cf of xanthomonas campestris pv. citri. | filamentous bacteriophages have very strict host specificities. experiments were performed to investigate whether the a protein of the filamentous phage cf, which infects xanthomonas campestris pv. citri but not x. campestris pv. oryzae, is involved in determining cf's host specificity. the gene encoding the a protein of cf was cloned and expressed in x. campestris pv. citri. the genomic dna of another filamentous bacteriophage, xf, which infects x. campestris pv. oryzae but not x. campestris pv ... | 1997 | 9139897 |
| crystal structure of glutamate-1-semialdehyde aminomutase: an alpha2-dimeric vitamin b6-dependent enzyme with asymmetry in structure and active site reactivity. | the three-dimensional structure of glutamate-1-semialdehyde aminomutase (ec 5.4.3.8), an alpha2-dimeric enzyme from synechococcus, has been determined by x-ray crystallography using heavy atom derivative phasing. the structure, refined at 2.4-a resolution to an r-factor of 18.7% and good stereochemistry, explains many of the enzyme's unusual specificity and functional properties. the overall fold is that of aspartate aminotransferase and related b6 enzymes, but it also has specific features. the ... | 1997 | 9144156 |
| the xanthomonas campestris gumd gene required for synthesis of xanthan gum is involved in normal pigmentation and virulence in causing black rot. | a cloned 4.1-kb ecori fragment from xanthomonas campestris pv. campestris was previously shown to complement the non-mucoid mutant p22 and increase xanthan gum production after being transformed into the wild-type strain xc17. the gene responsible for these effects was identified, sequenced, and shown to be the gumd gene which has previously been proposed to encode glucose transferase activity, an enzyme required for adding the first glucose residue to the isoprenoid glycosyl carrier lipid durin ... | 1997 | 9144435 |
| hrpf of xanthomonas campestris pv. vesicatoria encodes an 87-kda protein with homology to noix of rhizobium fredii. | the gram-negative bacterium xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease on pepper and tomato plants. the main hrp (hypersensitive reaction and pathogenicity) gene cluster in x. campestris pv. vesicatoria spans a 23-kb chromosomal region, comprising six complementation groups designated hrpa to hrpf. analysis of the hrpf locus revealed a single open reading frame encoding hrpf (86.4 kda). hrpf is predominantly hydrophilic, and contains two hydrophobic doma ... | 1997 | 9150597 |
| a novel regulatory system required for pathogenicity of xanthomonas campestris is mediated by a small diffusible signal molecule. | mutations in the seven clustered rpf genes cause downregulated synthesis of extracellular enzymes and reduced virulence of xanthomonas campestris pathovar campestris (xcc). the phenotype of mutants in one of the genes, rpff, can be restored by a diffusible extracellular factor (dsf) produced by all xcc strains tested, apart from rpff and rpfb mutants. dsf accumulates in early stationary phase (when synthesis of enzymes is maximal), but levels decline subsequently. addition of dsf to exponentiall ... | 1997 | 9179849 |
| isolation and analysis of the xanthomonas alkyl hydroperoxide reductase gene and the peroxide sensor regulator genes ahpc and ahpf-oxyr-orfx. | from xanthomonas campestris pv. phaseoli, we have isolated by two independent methods genes involved in peroxide detoxification (ahpc and ahpf), a gene involved in peroxide sensing and transcription regulation (oxyr), and a gene of unknown function (orfx). amino acid sequence analysis of ahpc, ahpf, and oxyr showed high identity with bacterial homologs. orfx was a small cysteine-rich protein with no significant homology to known proteins. the genes ahpc, ahpf, oxyr, and orfx were arranged in a h ... | 1997 | 9190810 |
| characterization of transcription organization and analysis of unique expression patterns of an alkyl hydroperoxide reductase c gene (ahpc) and the peroxide regulator operon ahpf-oxyr-orfx from xanthomonas campestris pv. phaseoli. | we have analyzed the transcription organization of ahpc, ahpf, oxyr, and orfx from xanthomonas campestris pv. phaseoli. ahpc was transcribed as a monocistronic 0.6-kb mrna, while ahpf-oxyr-orfx were transcribed as a polycistronic approximately 3.0-kb-long mrna. the novel transcription organization of these genes has not observed in other bacteria. western analysis showed that oxidants (peroxides and superoxide anions), a thiol reagent (n-ethylmaleimide), and cdcl2 caused large increases in the s ... | 1997 | 9190811 |
| sequence and copy number of the xanthomonas campestris pv. campestris gene encoding 16s rrna. | a 6.7-kb sau3a1 fragment containing ribosomal rna genes was cloned from the chromosome of xanthomonas campestris pv. campestris strain 17 by a pcr-based strategy. nucleotide sequence was determined for the 16s rrna gene (1,544 nt). this gene has a g+c content of 54.9% which is similar to the 16s rrna genes of escherichia coli and pseudomonas aeruginosa but different from the value reported for the whole x. campestris chromosome (64%). sequence alignment revealed that aggagg is consensus for ribo ... | 1997 | 9199181 |
| molecular characterization of the gene coding for threonine dehydrogenase in xanthomonas campestris. | the xanthomonas campestris pv. campestris 17 gene tdh, which codes for the threonine dehydrogenase (tdh), was cloned and sequenced. the deduced gene product, a polypeptide consisting of 340 amino acids (mr = 37,048), has 63.5% identity to the e. coli tdh in amino acid sequence and shares residue conservation with the alcohol/polyol dehydrogenases from different organisms. tdh activity was not detectable in the tdh mutant constructed by gene replacement; however, the enzyme activity in the mutant ... | 1997 | 9199186 |
| isolation and characterization of a multiple peroxide resistant mutant from xanthomonas campestris pv. phaseoli. | we have isolated a spontaneous multiple peroxide resistant xanthamonas campestris pv. phaseoli mutant (xphr). in the presence of peroxides, the mutant had a higher growth rate than the parent. it also had a greater than 100-fold increase in resistance levels to h2o2 killing but only slightly more resistance to tert-butyl hydroperoxide killing. increases in activity were detected for the peroxide scavenging enzymes catalase (100-fold) and ahpc (over 30-fold). also observed was cross-resistance to ... | 1997 | 9228787 |
| is element isxc6 of xanthomonas campestris pv. campestris. | an insertion sequence element, isxc6, was isolated from xanthomonas campestris pv. campestris 17 (xc17). sequence analysis showed that it is 1,500 bp long and has 20-bp perfect inverted repeat ends. upon transposition, a direct repeat taattc was generated, flanking this is. no significant homology was observed between this sequence and other sequences in database. results of southern hybridization showed that multiple copies of isxc6 were present in 7 strains of xanthomonas examined. | 1997 | 9254017 |
| use of arabidopsis recombinant inbred lines reveals a monogenic and a novel digenic resistance mechanism to xanthomonas campestris pv campestris. | infiltration of the arabidopsis thaliana accession landsberg erecta (ler) with xanthomonas campestris pv campestris isolate 2d520 results in extensive necrosis and limited chlorosis within 5-6 days post-inoculation (d.p.i.), which can lead to systemic necrosis within 23 d.p.i. in contrast, the accession columbia (col) remains asymptomatic after infiltration. although both accessions support bacterial growth, 5-28-fold more bacteria are present in ler than in col leaf tissue. inheritance studies ... | 1997 | 9263449 |
| a secreted salmonella protein with homology to an avirulence determinant of plant pathogenic bacteria. | bacterial pathogens have evolved sophisticated mechanisms to interact with their hosts. a specialized type iii protein secretion system capable of translocating bacterial proteins into host cells has emerged as a central factor in the interaction between a variety of mammalian and plant pathogenic bacteria with their hosts. here we describe avra, a novel target of the centisome 63 type iii protein secretion system of salmonella enterica. avra shares sequence similarity with yopj of the animal pa ... | 1997 | 9275221 |
| improved broad-host-range rk2 vectors useful for high and low regulated gene expression levels in gram-negative bacteria. | this report describes the construction and use of improved broad-host-range expression vectors based on the previously constructed pjb137 and pjb653 plasmids (blatny et al., 1997). these vectors contain the minimal replicon of rk2 and the inducible pu or pm promoters together with their regulatory xylr or xyls genes, respectively, from the pseudomonas putida tol plasmid pwwo. a set of atg vectors were derived from pjb653, and these vectors are characterized by the relatively small size, the pres ... | 1997 | 9281494 |
| yersinia signals macrophages to undergo apoptosis and yopj is necessary for this cell death. | pathogenic yersinia spp. carry a large common plasmid that encodes a number of essential virulence determinants. included in these factors are the yersinia-secreted proteins called yops. we analyzed the consequences of wild-type and mutant strains of yersinia pseudotuberculosis interactions with the macrophage cell line raw264. 7 and murine bone marrow-derived macrophages. wild-type y. pseudotuberculosis kills approximately 70% of infected raw264.7 macrophages and marrow-derived macrophages afte ... | 1997 | 9294220 |
| induction of extracellular matrix glycoproteins in brassica petioles by wounding and in response to xanthomonas campestris. | a panel of monoclonal antibodies that recognize plant extracellular matrix glycoproteins previously implicated in plant-microbe interactions was used to study the effects of pathogen inoculation and wounding on glycoproteins in petioles of brassica campestris. the panel of monoclonals comprised two sets: jim11, jim12, and jim20 recognize epitopes carried on hydroxyproline-rich glycoproteins (hrgps) (m. smallwood, a. beven, n. donovan, s. j. neitl, j. peart, k. roberts, and j. p. knox, plant j. 5 ... | 1997 | 9304856 |
| evaluation of the role of reca protein in plant virulence with reca mutants of xanthomonas campestris pv. campestris. | xanthomonas campestris pv. campestris nrrl b1459 reca mutants were isolated by recombination with an interrupted rhizobium etli reca gene and selection of double recombinants. the mutants were impaired in homologous genetic recombination and in dna repair as judged by their sensitivity to methyl-methane-sulfonate and to uv irradiation; these defects are complemented in trans by the r. etli reca gene. virulence of x. campestris pv. campestris nrrl b1459 to cabbage is considerably diminished by th ... | 1997 | 9304862 |
| the activity of lipid a and core components of bacterial lipopolysaccharides in the prevention of the hypersensitive response in pepper. | pre-treatment of leaves of pepper (capsicum annuum) with lipopolysaccharide (lps) preparations from enteric bacteria and xanthomonas campestris could prevent the hypersensitive response caused by an avirulent x. campestris strain. by use of a range of deep-rough mutants, the minimal structure in salmonella lps responsible for the elicitation of this effect was determined to be lipid a attached to a disaccharide of 2-keto-3-deoxyoctulosonate; lipid a alone and the free core oligosaccharide from a ... | 1997 | 9304863 |
| cloning of the acef gene encoding the phosphomannose isomerase and gdp-mannose pyrophosphorylase activities involved in acetan biosynthesis in acetobacter xylinum. | the acef gene from acetobacter xylinum was identified and cloned from a genomic dna library. the complete dna sequence was determined and computer analysis of the translated gene sequence revealed homology with the deduced amino acid sequence of xanb from xanthomonas campestris. therefore acef is likely to encode a bifunctional enzyme with mannose-6-phosphate isomerase (pmi) and gdp-mannose pyrophosphorylase (gmp) activities. pmi and gmp activities were detected in strains of escherichia coli ex ... | 1997 | 9311139 |
| increased elisa sensitivity using a modified extraction buffer for detection of xanthomonas campestris pv. vesicatoria in leaf tissue. | in vitro and in planta sensitivity of an indirect enzyme-linked immunoassay technique, using a monoclonal antibody specific for the lipopolysaccharide (lps) of xanthomonas campestris pv. vesicatoria, was increased 10-fold by using a new extraction buffer (gl of: kh2po4, 2; nahpo4, 11.5; edta disodium, 0.14; thimerosal, 0.02; and lysozyme, 0.2). the procedure improved sensitivity without increasing background levels. in vitro, the limit of detection was between 1 x 10(7) and 1 x 10(8) cells ml-1 ... | 1997 | 9351221 |
| yersinia enterocolitica induces apoptosis in macrophages by a process requiring functional type iii secretion and translocation mechanisms and involving yopp, presumably acting as an effector protein. | yersiniae, causative agents of plague and gastrointestinal diseases, secrete and translocate yop effector proteins into the cytosol of macrophages, leading to disruption of host defense mechanisms. it is shown in this report that yersinia enterocolitica induces apoptosis in macrophages and that this effect depends on yopp. functional secretion and translocation mechanisms are required for yopp to act, strongly suggesting that this protein exerts its effect intracellularly, after translocation in ... | 1997 | 9356502 |
| production of xanthan gum by sphingomonas bacteria carrying genes from xanthomonas campestris. | twelve genes coding for assembly, acetylation, pyruvylation, polymerization, and secretion of the polysaccharide xanthan gum are clustered together on the chromosome of the bacterium xanthomonas campestris. these genes (gumbcdefghijklm) are sufficient for synthesis of xanthan gum when placed in bacteria from a different genus, sphingomonas. the polysaccharide from the recombinant microorganism is largely indistinguishable, structurally and functionally, from native xanthan gum. these results dem ... | 1997 | 9366091 |
| the deinococcus radiodurans uvr a gene: identification of mutation sites in two mitomycin-sensitive strains and the first discovery of insertion sequence element from deinobacteria. | deinococcus radiodurans (dr) possesses a prominent ability to repair the dna injury induced by various dna-damaging agents including mitomycin c (mc), ultraviolet light (uv) and ionizing radiation. dna damage resistance was restored in mc sensitive (mc(s)) mutants 2621 and 3021 by transforming with dnas of four cosmid clones derived from the gene library of strain kd8301, which showed wild type (wt) phenotype to dna-damaging agents. gene affected by mutation (mtca or mtcb) in both mutants was cl ... | 1997 | 9370272 |
| unusual structure of the tonb-exb dna region of xanthomonas campestris pv. campestris: tonb, exbb, and exbd1 are essential for ferric iron uptake, but exbd2 is not. | the nucleotide sequence of a 3.6-kb hindiii-smai dna fragment of xanthomonas campestris pv. campestris revealed four open reading frames which, based on sequence homologies, were designated tonb, exbb, exbd1, and exbd2. analysis of translational fusions to alkaline phosphatase and beta-galactosidase confirmed that the tonb, exbb, exbd1, and exbd2 proteins are anchored in the cytoplasmic membrane. the tonb protein of x. campestris pv. campestris lacks the conserved (glu-pro)n and (lys-pro)m repea ... | 1997 | 9371459 |
| xanthomonas campestris pv. campestris lpsi and lpsj genes encoding putative proteins with sequence similarity to the alpha- and beta-subunits of 3-oxoacid coa-transferases are involved in lps biosynthesis. | a 2.1-kb smai-ecori dna fragment upstream of the xana and xanb genes of xanthomonas campestris pv. campestris carries two orfs encoding putative proteins with sequence similarities to the alpha- and beta-subunits of 3-oxoacid-coa transferases. the two orfs were termed lpsi and lpsj because strains carrying appropriate mutations showed an autoagglutination phenotype and because lipopolysaccharides of these mutant strains were altered according to silver-stained polyacrylamide gels. the monosaccha ... | 1997 | 9385134 |
| transcriptional analysis of the threonine dehydrogenase gene of xanthomonas campestris. | the nucleotide sequence has previously been determined for the xanthomonas campestris pv. campestris gene coding for threonine dehydrogenase (tdh). flanking this gene are the upstream region possessing promoter activity and the downstream perfect inverted repeat having potential to form a stem-loop structure which resembles a transcription terminator. in addition, northern blot analysis suggested the transcript of this gene to be monocistronic. in the present study, the essential region for prom ... | 1997 | 9398597 |
| atzc is a new member of the amidohydrolase protein superfamily and is homologous to other atrazine-metabolizing enzymes. | pseudomonas sp. strain adp metabolizes atrazine to cyanuric acid via three plasmid-encoded enzymes, atza, atzb, and atzc. the first enzyme, atza, catalyzes the hydrolytic dechlorination of atrazine, yielding hydroxyatrazine. the second enzyme, atzb, catalyzes hydroxyatrazine deamidation, yielding n-isopropylammelide. in this study, the third gene in the atrazine catabolic pathway, atzc, was cloned from a pseudomonas sp. strain adp cosmid library as a 25-kb ecori dna fragment in escherichia coli. ... | 1998 | 9422605 |
| complementation analysis of the dichelobacter nodosus fimn, fimo, and fimp genes in pseudomonas aeruginosa and transcriptional analysis of the fimnop gene region. | the causative agent of ovine footrot, the gram-negative anaerobe dichelobacter nodosus, produces polar type iv fimbriae, which are the major protective antigens. the d. nodosus genes fimn, fimo, and fimp are homologs of the pseudomonas aeruginosa fimbrial assembly genes, pilb, pilc, and pild, respectively. both the pild and fimp genes encode prepilin peptidases that are responsible for cleavage of the leader sequence from the immature fimbrial subunit. to investigate the functional similarity of ... | 1998 | 9423871 |
| arabidopsis thaliana class iv chitinase is early induced during the interaction with xanthomonas campestris. | endochitinases are widely distributed among higher plants, including a number of important crop species. they are generally considered to be involved in plant defence against potential pathogens. we have cloned a class iv chitinase gene (atchitiv) from arabidopsis thaliana. southern blot analysis allowed the detection of two cross-hybridising genes in the a. thaliana genome. atchitiv transcripts are detected in seedpods, but not in roots, inflorescence stems, leaves and flowers of healthy plants ... | 1997 | 9426222 |
| structure of proline iminopeptidase from xanthomonas campestris pv. citri: a prototype for the prolyl oligopeptidase family. | the proline iminopeptidase from xanthomonas campestris pv. citri is a serine peptidase that catalyses the removal of n-terminal proline residues from peptides with high specificity. we have solved its three-dimensional structure by multiple isomorphous replacement and refined it to a crystallographic r-factor of 19.2% using x-ray data to 2.7 a resolution. the protein is folded into two contiguous domains. the larger domain shows the general topology of the alpha/beta hydrolase fold, with a centr ... | 1998 | 9427736 |
| purification and expression of the gene iii protein from filamentous phage phi lf. | the gene iii protein (piii) from phi lf, a filamentous phage of xanthomonas campestris pv.campestris, was purified by gel filtration with fplc. the giii coding region was amplified by pcr, which was then cloned into puc18 and expressed in escherichia coli. the size of both piii, purified from phage particle and expressed in e. coli, is similar to the value deduced from the nucleotide sequence as shown by western blot analysis. this is different from the case in ff phages (f1, fd, and m13), in wh ... | 1998 | 9439620 |
| specific amino acid substitutions in the proline-rich motif of the rhizobium meliloti exop protein result in enhanced production of low-molecular-weight succinoglycan at the expense of high-molecular-weight succinoglycan. | the production of the acidic exopolysaccharide succinoglycan (eps i) by rhizobium meliloti exop* mutants expressing an exop protein lacking its c-terminal cytoplasmic domain and by mutants characterized by specific amino acid substitutions in the proline-rich motif (rx4px2px4spkx9ixgxmxgxg) located from positions 443 to 476 of the exop protein was analyzed. the absence of the c-terminal cytoplasmic exop domain (positions 484 to 786) and the substitution of both arginine443 by isoleucine443 and p ... | 1998 | 9440529 |
| homology and functional similarity of an hrp-linked pathogenicity locus, dspef, of erwinia amylovora and the avirulence locus avre of pseudomonas syringae pathovar tomato. | the "disease-specific" (dsp) region next to the hrp gene cluster of erwinia amylovora is required for pathogenicity but not for elicitation of the hypersensitive reaction. a 6.6-kb apparent operon, dspef, was found responsible for this phenotype. the operon contains genes dspe and dspf and is positively regulated by hrpl. a blast search revealed similarity in the dspe gene to a partial sequence of the avre locus of pseudomonas syringae pathovar tomato. the entire avre locus was sequenced. homolo ... | 1998 | 9448330 |
| phosphomannose isomerase of xanthomonas campestris: a zinc activated enzyme. | phosphomannose isomerase (pmi, ec 5.3.1.8) was purified to homogeneity from a wild strain of xanthomonas campestris. the apparent molecular weight as determined by sds-page and sephadex g-100 superfine was found to be 58 kda. the purified enzyme showed a single band on acrylamide gel electrophocusing with pi = 5.25. the optimum ph was 7.0 and the km for d-mannose-6-phosphate was 2 mm. pmi can be activated by bivalent cations with the order of co2+>zn2+>mn2+>ni2+>ca2+. addition of low concentrati ... | 1997 | 9450661 |
| environmental regulation of salmonella typhi invasion-defective mutants. | salmonella typhi is the etiologic agent of human typhoid. during infection, s. typhi adheres to and invades epithelial and m cells that line the distal ileum. to survive in the human host, s. typhi must overcome numerous complex extracellular and intracellular environments. since relatively little is known about s. typhi pathogenesis, studies were initiated to identify s. typhi genes involved in the early steps of interaction with the host and to evaluate the environmental regulation of these ge ... | 1998 | 9453627 |
| microbiological and clinical aspects of infection associated with stenotrophomonas maltophilia. | the gram-negative bacterium stenotrophomonas maltophilia is increasingly recognized as an important cause of nosocomial infection. infection occurs principally, but not exclusively, in debilitated and immunosuppressed individuals. management of s. maltophilia-associated infection is problematic because many strains of the bacterium manifest resistance to multiple antibiotics. these difficulties are compounded by methodological problems in in vitro susceptibility testing for which there are, as y ... | 1998 | 9457429 |
| assignment of biochemical functions to glycosyl transferase genes which are essential for biosynthesis of exopolysaccharides in sphingomonas strain s88 and rhizobium leguminosarum. | glycosyl transferases which recognize identical substrates (nucleotide-sugars and lipid-linked carbohydrates) can substitute for one another in bacterial polysaccharide biosynthesis, even if the enzymes originate in different genera of bacteria. this substitution can be used to identify the substrate specificities of uncharacterized transferase genes. the spsk gene of sphingomonas strain s88 and the pssde genes of rhizobium leguminosarum were identified as encoding glucuronosyl-(b1-->4)-glucosyl ... | 1998 | 9457861 |
| alcaligenes eutrophus as a bacterial chromate sensor. | in alcaligenes eutrophus ch34, determinants encoding inducible resistance to chromate (chr) and to cobalt and nickel (cnr) are located adjacent to each other on plasmid pmol28. to develop metal-sensing bacterial strains, a cloned part of plasmid pmol28, which contains both determinants, was mutated with tn5-lacz. the chr::lacz fusions were specifically induced by chromium; cnr was induced best by ni2+ but was also induced by co2+, mn2+, chromate, cu2+, cd2+, and zn2+. the broad-host-range incp1 ... | 1998 | 9464379 |
| characterization of marine temperate phage-host systems isolated from mamala bay, oahu, hawaii. | to understand the ecological and genetic role of viruses in the marine environment, it is critical to know the infectivity of viruses and the types of interactions that occur between marine viruses and their hosts. we isolated four marine phages from turbid plaques by using four indigenous bacterial hosts obtained from concentrated water samples from mamala bay, oahu, hawaii. two of the rod-shaped bacterial hosts were identified as sphingomonas paucimobilis and flavobacterium sp. all of the phag ... | 1998 | 9464390 |
| optimization of exopolysaccharide production by lactobacillus delbrueckii subsp. bulgaricus rr grown in a semidefined medium. | the optimal fermentation temperature, ph, and bacto-casitone (difco laboratories, detroit, mich.) concentration for production of exopolysaccharide by lactobacillus delbrueckii subsp. bulgaricus rr in a semidefined medium were determined by using response surface methods. the design consisted of 20 experiments, 15 unique combinations, and five replications. all fermentations were conducted in a fermentor with a 2.5-liter working volume and were terminated when 90% of the glucose in the medium ha ... | 1998 | 9464404 |
| ethylene regulates the susceptible response to pathogen infection in tomato. | ethylene evolution occurs concomitantly with the progression of disease symptoms in response to many virulent pathogen infections in plants. a tomato mutant impaired in ethylene perception-never ripe-exhibited a significant reduction in disease symptoms in comparison to the wild type after inoculations of both genotypes with virulent bacterial (xanthomonas campestris pv vesicatoria and pseudomonas syringae pv tomato) and fungal (fusarium oxysporum f sp lycopersici) pathogens. bacterial spot dise ... | 1998 | 9501111 |
| isolation of wild xanthomonas strains from agricultural produce, their characterization and potential related to polysaccharide production. | one hundred fifty wild strains of xanthomonas were isolated on five selective and nonselective media. the comparative effectivity of the five media has been discussed. fifteen polysaccharide-producing strains shortlisted were identified up to species level. these were studied for polysaccharide production in shake flasks using ym media. the highest final yield of 21.3 g/l of the amount of carbon source supplied has been obtained in the optimum medium in shake-flask experiments from xanthomonas c ... | 1997 | 9508555 |
| external loops at the c terminus of erwinia chrysanthemi pectate lyase c are required for species-specific secretion through the out type ii pathway. | the type ii secretion system (main terminal branch of the general secretion pathway) is used by diverse gram-negative bacteria to secrete extracellular proteins. proteins secreted by this pathway are synthesized with an n-terminal signal peptide which is removed upon translocation across the inner membrane, but the signals which target the mature proteins for secretion across the outer membrane are unknown. the plant pathogens erwinia chrysanthemi and erwinia carotovora secrete several isozymes ... | 1998 | 9515910 |
| identification and temperature regulation of legionella pneumophila genes involved in type iv pilus biogenesis and type ii protein secretion. | previously, we had isolated by transposon mutagenesis a legionella pneumophila mutant that appeared defective for intracellular iron acquisition. while sequencing in the proximity of the mini-tn10 insertion, we found a locus that had a predicted protein product with strong similarity to pilb from pseudomonas aeruginosa. pilb is a component of the type ii secretory pathway, which is required for the assembly of type iv pili. consequently, the locus was cloned and sequenced. within this 4-kb regio ... | 1998 | 9529113 |
| isolation and characterization of the xanthomonas campestris rpoh gene coding for a 32-kda heat shock sigma factor. | degenerate oligonucleotide primers corresponding to the conserved regions of bacterial heat shock sigma factor rpoh (sigma 32) were used to amplify a 190-bp fragment by pcr on the x. campestris pv. campestris strain 11 chromosome. using this fragment as a probe, plasmid pxc57 carrying a 4.7-kb insert was isolated from a genomic library of xc11. sequence analysis of a stretch of 2,053 bp from the pxc57 insert revealed an orf encoding a polypeptide of 291 aa (32,854 dal) which displays 59.6% and 5 ... | 1998 | 9535756 |
| xanthomonas campestris pv. campestris gum mutants: effects on xanthan biosynthesis and plant virulence. | xanthan is an industrially important exopolysaccharide produced by the phytopathogenic, gram-negative bacterium xanthomonas campestris pv. campestris. it is composed of polymerized pentasaccharide repeating units which are assembled by the sequential addition of glucose-1-phosphate, glucose, mannose, glucuronic acid, and mannose on a polyprenol phosphate carrier (l. ielpi, r. o. couso, and m. a. dankert, j. bacteriol. 175:2490-2500, 1993). a cluster of 12 genes in a region designated xpsi or gum ... | 1998 | 9537354 |
| production of cell-free xanthan fermentation broth by cell adsorption on fibers | xanthan gum is a microbial polysaccharide widely used in food and oil-drilling industries. xanthan gum produced from the current commercial fermentation process usually contains cells and cell debris, which lower the filterability of the xanthan solution and limit its applications. the production of cell-free xanthan gum fermentation broth is thus desirable. the feasibility of removing cells from the xanthan fermentation broth by cell adsorption to various woven fibrous materials was studied. it ... | 1998 | 9548777 |