Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| the aroq and phea domains of the bifunctional p-protein from xanthomonas campestris in a context of genomic comparison. | the gene (denoted aroqp.phea) encoding the bifunctional p-protein (chorismate mutase-p/prephenate dehydratase) from xanthomonas campestris was cloned. aroqp.phea is essential for l-phenylalanine biosynthesis. dna sequencing of the smallest subclone capable of functional complementation of an escherichia coli phenylalanine auxotroph revealed a putative open reading frame (orf) of 1200 bp that would encode a 43,438-da protein. aroqp.phea exhibited 51% amino acid identity with a pseudomonas stutzer ... | 1997 | 9689222 |
| 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 |
| cloning and characterization of a member of the xanthomonas avr/pth gene family that evades all commercially utilized cotton r genes in the united states. | abstract the highly virulent african strains of xanthomonas campestris pv. malvacearum are quarantined pathogens in the united states and can evade or overcome all commercially utilized resistance (r) genes in cotton grown in the united states including the entire set of host differential lines used to distinguish 19 races of the pathogen. nevertheless, the african strains carry multiple dna fragments that strongly hybridize with members of the xanthomonas avirulence (avr)/pathogenicity (pth) ge ... | 1997 | 18945013 |
| mutation in the avrbs1 avirulence gene of xanthomonas campestris pv. vesicatoria influences survival of the bacterium in soil and detached leaf tissue. | abstract the role of the avrbs1 avirulence gene of xanthomonas campestris pv. vesicatoria in survival of the bacterium was investigated by testing two strains that differ in the structure and function of the gene in 37 different soil types of barbados and detached leaf tissue of four pepper genotypes. one strain carried a mutation in the avrbs1 gene and lacked avirulence activity, while the other expressed wild-type avrbs1 activity. in 30 to 32 soil types and all leaf tissue tested, the mutant s ... | 1997 | 18945068 |
| 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 |
| monitoring impact of a pesticide treatment on bacterial soil communities by metabolic and genetic fingerprinting in addition to conventional testing procedures. | herbogil (dinoterb), a reference herbicide, the mineral oil oleo (paraffin oil used as an additive to herbicides), and goltix (metamitron) were taken as model compounds for the study of impacts on microbial soil communities. after the treatment of soil samples, effects on metabolic sum parameters were determined by monitoring substrate-induced respiration (sir) and dehydrogenase activity, as well as carbon and nitrogen mineralization. these conventional ecotoxicological testing procedures are us ... | 1998 | 9687435 |
| estimating photosynthesis and concurrent export rates in c3 and c4 species at ambient and elevated co21,2 | the ability of 21 c3 and c4 monocot and dicot species to rapidly export newly fixed c in the light at both ambient and enriched co2 levels was compared. photosynthesis and concurrent export rates were estimated during isotopic equilibrium of the transport sugars using a steady-state 14co2-labeling procedure. at ambient co2 photosynthesis and export rates for c3 species were 5 to 15 and 1 to 10 &mgr;mol c m-2 s-1, respectively, and 20 to 30 and 15 to 22 &mgr;mol c m-2 s-1, respectively, for c4 sp ... | 1998 | 9576790 |
| evidence for the preemptive nature of tomato race 3 of xanthomonas campestris pv. vesicatoria in florida. | abstract until recently, tomato race 1 (t1) of xanthomonas campestris pv. vesicatoria was the only race causing bacterial spot of tomato in florida. in 1991, tomato race 3 (t3) was first identified in 3 of 13 tomato production fields surveyed. by 1994, t3 was observed in 21 of 28 fields and was the only race identified in 14 fields. in field studies, tomato genotypes with resistance to either t1 or t3 or susceptibility to both were co-inoculated with strains of both races. lesions on 10 plants i ... | 1998 | 18944996 |
| structure-activity relationships for some diamine, triamine and schiff base derivatives and their copper(ii) complexes. | ethylenediamine (en), putrescine (pu), diethylenetriamine (dien), dipropylenetriamine (dpta), spermidine (spmd) and their cu(ii) compounds as well as the schiff bases with 2-furaldehyde (dienoo), 2- thiophenecarboxaldehyde (dienss) and pyrrole-2-carboxaldehyde (diennn) of dien and that of dpta with 2- thiophenecarboxaldehyde (dptass), were prepared and characterised. they were tested against bacillus substilis, bacillus cereus, staphylococcus aureus, escherichia coli, proteus vulgaris and xantho ... | 1998 | 18475868 |
| molecular and biotechnological aspects of microbial proteases. | proteases represent the class of enzymes which occupy a pivotal position with respect to their physiological roles as well as their commercial applications. they perform both degradative and synthetic functions. since they are physiologically necessary for living organisms, proteases occur ubiquitously in a wide diversity of sources such as plants, animals, and microorganisms. microbes are an attractive source of proteases owing to the limited space required for their cultivation and their ready ... | 1998 | 9729602 |
| insertion sequences. | insertion sequences (iss) constitute an important component of most bacterial genomes. over 500 individual iss have been described in the literature to date, and many more are being discovered in the ongoing prokaryotic and eukaryotic genome-sequencing projects. the last 10 years have also seen some striking advances in our understanding of the transposition process itself. not least of these has been the development of various in vitro transposition systems for both prokaryotic and eukaryotic e ... | 1998 | 9729608 |
| counterselectable markers: untapped tools for bacterial genetics and pathogenesis. | 1998 | 9712740 | |
| 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 |
| d-subgenome bias of xcm resistance genes in tetraploid gossypium (cotton) suggests that polyploid formation has created novel avenues for evolution. | a detailed rflp map was used to determine the chromosomal locations and subgenomic distributions of cotton (gossypium) genes/qtls that confer resistance to the bacterial blight pathogen, xanthomonas campestris pv. malvacearum (xcm). genetic mapping generally corroborated classic predictions regarding the number and dosage effects of genes conferring xcm resistance. one recessive allele (b6) was a noteworthy exception to the genetic dominance of most plant resistance alleles. this recessive allel ... | 1998 | 9691052 |
| one of two osmc homologs in bacillus subtilis is part of the sigmab-dependent general stress regulon. | in this report we present the identification and analysis of two bacillus subtilis genes, ykla and ykza, which are homologous to the partially rpos-controlled osmc gene from escherichia coli. the ykla gene is expressed at higher levels in minimal medium than in rich medium and is driven by a putative vegetative promoter. expression of ykza is not medium dependent but increases dramatically when cells are exposed to stress and starvation. this stress-induced increase in ykza expression is absolut ... | 1998 | 9696771 |
| genetically engineered broad-spectrum disease resistance in tomato. | resistance in tomato to the bacterial pathogen pseudomonas syringae pathovar tomato requires pto and prf. mutations that eliminate prf show a loss of both pto resistance and sensitivity to the organophosphate insecticide fenthion, suggesting that prf controls both phenotypes. herein, we report that the overexpression of prf leads to enhanced resistance to a number of normally virulent bacterial and viral pathogens and leads to increased sensitivity to fenthion. these plants express levels of sal ... | 1998 | 9707642 |
| different requirements for eds1 and ndr1 by disease resistance genes define at least two r gene-mediated signaling pathways in arabidopsis. | the arabidopsis genes eds1 and ndr1 were shown previously by mutational analysis to encode essential components of race-specific disease resistance. here, we examined the relative requirements for eds1 and ndr1 by a broad spectrum of resistance (r) genes present in three arabidopsis accessions (columbia, landsberg-erecta, and wassilewskija). we show that there is a strong requirement for eds1 by a subset of r loci (rpp2, rpp4, rpp5, rpp21, and rps4), conferring resistance to the biotrophic oomyc ... | 1998 | 9707643 |
| molecular characterization and sequence of a methionine biosynthetic locus from pseudomonas syringae. | two methionine biosynthetic genes in pseudomonas syringae pv. syringae, metx and metw, were isolated, sequenced, and evaluated for their roles in methionine biosynthesis and bacterial fitness on leaf surfaces. the metxw locus was isolated on a 1.8-kb dna fragment that was required for both methionine prototrophy and wild-type epiphytic fitness. sequence analysis identified two consecutive open reading frames (orfs), and in vitro transcription-translation experiments provided strong evidence that ... | 1998 | 9721288 |
| characterization of the hrpc and hrprs operons of pseudomonas syringae pathovars syringae, tomato, and glycinea and analysis of the ability of hrpf, hrpg, hrcc, hrpt, and hrpv mutants to elicit the hypersensitive response and disease in plants. | the species pseudomonas syringae encompasses plant pathogens with differing host specificities and corresponding pathovar designations. p. syringae requires the hrp (type iii protein secretion) system, encoded by a 25-kb cluster of hrp and hrc genes, in order to elicit the hypersensitive response (hr) in nonhosts or to be pathogenic in hosts. dna sequence analysis of the hrpc and hrprs operons of p. syringae pv. syringae 61 (brown spot of beans), p. syringae pv. glycinea u1 (bacterial blight of ... | 1998 | 9721291 |
| negative regulation of hrp genes in pseudomonas syringae by hrpv. | mutations in the five hrp and hrc genes in the hrpc operon of the phytopathogen pseudomonas syringae pv. syringae 61 have different effects on bacterial interactions with host and nonhost plants. the hrcc gene within the hrpc operon encodes an outer membrane component of the hrp secretion system that is conserved in all type iii protein secretion systems and is required for most pathogenic phenotypes and for secretion of the hrpz harpin to the bacterial milieu. the other four genes (in order), h ... | 1998 | 9721292 |
| cloning, nucleotide sequence, and expression in escherichia coli of levansucrase genes from the plant pathogens pseudomonas syringae pv. glycinea and p. syringae pv. phaseolicola. | plant-pathogenic bacteria produce various extracellular polysaccharides (epss) which may function as virulence factors in diseases caused by these bacteria. the eps levan is synthesized by the extracellular enzyme levansucrase in pseudomonas syringae, erwinia amylovora, and other bacterial species. the lsc genes encoding levansucrase from p. syringae pv. glycinea pg4180 and p. syringae pv. phaseolicola ncppb 1321 were cloned, and their nucleotide sequences were determined. heterologous expressio ... | 1998 | 9726857 |
| initial transformations in the biodegradation of benzothiazoles by rhodococcus isolates. | benzothiazole-2-sulfonate (btso3) is one of the side products occurring in 2-mercaptobenzothiazole (mbt) production wastewater. we are the first to isolate an axenic culture capable of btso3 degradation. the isolate was identified as a rhodococcus erythropolis strain and also degraded 2-hydroxybenzothiazole (obt) and benzothiazole (bt), but not mbt, which was found to inhibit the biodegradation of obt, bt, and btso3. in anaerobic resting cell assays, btso3 was transformed into obt in stoichiomet ... | 1998 | 9726870 |
| molecular identification of a stenotrophomonas species used in the bioassay for erythromycin in aquaculture samples. | a bacterial strain isolated from aquaculture pond slurry, which was extremely sensitive to erythromycin, was used to detect erythromycin at levels as low as 0.05 micrograms ml-1 in aquaculture water, sediments and soil samples. identification of the indicator organism was attempted by 16s rrna sequencing, biochemical profile, fatty-acid analysis and polymerase chain reaction (pcr). genbank comparison showed that the 16s rrna sequence of the strain was similar to those of more than 20 copies of x ... | 1998 | 9727203 |
| hrpw of erwinia amylovora, a new harpin that contains a domain homologous to pectate lyases of a distinct class. | harpins, such as hrpn of erwinia amylovora, are extracellular glycine-rich proteins that elicit the hypersensitive reaction (hr). we identified hrpw of e. amylovora, which encodes a protein similar to known harpins in that it is acidic, rich in glycine and serine, and lacks cysteine. a putative hrpl-dependent promoter was identified upstream of hrpw, and western blot analysis of hrpl mutants indicated that the production of hrpw is regulated by hrpl. hrpw is secreted via the hrp (type iii) pathw ... | 1998 | 9748455 |
| the pseudomonas syringae pv. tomato hrpw protein has domains similar to harpins and pectate lyases and can elicit the plant hypersensitive response and bind to pectate. | the host-specific plant pathogen pseudomonas syringae elicits the hypersensitive response (hr) in nonhost plants and secretes the hrpz harpin in culture via the hrp (type iii) secretion system. previous genetic evidence suggested the existence of another harpin gene in the p. syringae genome. hrpw was found in a region adjacent to the hrp cluster in p. syringae pv. tomato dc3000. hrpw encodes a 42. 9-kda protein with domains resembling harpins and pectate lyases (pels), respectively. hrpw has ke ... | 1998 | 9748456 |
| xanthan lyase of bacillus sp. strain gl1 liberates pyruvylated mannose from xanthan side chains. | when the bacterium bacillus sp. strain gl1 was grown in a medium containing xanthan as the carbon source, the viscosity of the medium decreased in association with growth, showing that the bacterium had xanthan-depolymerizing enzymes. one of the xanthan-depolymerizing enzymes (xanthan lyase) was present in the medium and was found to be induced by xanthan. the xanthan lyase purified from the culture fluid was a monomer with a molecular mass of 75 kda, and was most active at ph 5.5 and 50 degrees ... | 1998 | 9758797 |
| genetic characterization of pseudomonas syringae pv. syringae strains from stone fruits in california | strains of pseudomonas syringae pv. syringae were isolated from healthy and diseased stone fruit tissues sampled from 43 orchard sites in california in 1995 and 1996. these strains, together with p. syringae strains from other hosts and pathovars, were tested for pathogenicity and the presence of the syrb and syrc genes and were genetically characterized by using enterobacterial repetitive intergenic consensus (eric) primers and pcr. all 89 strains of p. syringae pv. syringae tested were moderat ... | 1998 | 9758805 |
| relatedness of strains of xanthomonas fragariae by restriction fragment length polymorphism, dna-dna reassociation, and fatty acid analyses | the levels of relatedness of strains of xanthomonas fragariae collected over several years from locations in canada and the united states were compared by determining fatty acid methyl ester profiles, restriction fragment length polymorphisms (rflp) based on pulsed-field gel electrophoresis (pfge) analysis, and dna-dna reassociation values. based on qualitative and quantitative differences in fatty acid profiles, the strains were divided into nine groups and four groups by the midi "10% rule" an ... | 1998 | 9758826 |
| pcr-based detection of the causal agent of watermark disease in willows (salix spp.) | the watermark disease, caused by brenneria salicis (formerly erwinia salicis), is of significant concern wherever tree-forming willows are grown or occur naturally. the movement of infected, asymptomatic cuttings is a major cause of pathogen dispersal. a reliable and sensitive diagnostic procedure is necessary for the safe movement of willow planting material. we derived primers from the nucleotide sequence of the 16s rrna gene of b. salicis for the development of a pcr to detect this pathogen. ... | 1998 | 9758827 |
| xanthan gum biosynthesis and application: a biochemical/genetic perspective. | xanthan gum is a complex exopolysaccharide produced by the plant-pathogenic bacterium xanthomonas campestris pv. campestris. it consists of d-glucosyl, d-mannosyl, and d-glucuronyl acid residues in a molar ratio of 2:2:1 and variable proportions of o-acetyl and pyruvyl residues. because of its physical properties, it is widely used as a thickener or viscosifier in both food and non-food industries. xanthan gum is also used as a stabilizer for a wide variety of suspensions, emulsions, and foams. ... | 1998 | 9763683 |
| iron-responsive gene regulation in a campylobacter jejuni fur mutant. | the expression of iron-regulated systems in gram-negative bacteria is generally controlled by the fur protein, which represses the transcription of iron-regulated promoters by using fe2+ as a cofactor. mutational analysis of the campylobacter jejuni fur gene was carried out by generation of a set of mutant copies of fur which had a kanamycin or chloramphenicol resistance gene introduced into the regions encoding the n and c termini of the fur protein. the mutated genes were recombined into the c ... | 1998 | 9765558 |
| novel rkp gene clusters of sinorhizobium meliloti involved in capsular polysaccharide production and invasion of the symbiotic nodule: the rkpk gene encodes a udp-glucose dehydrogenase. | the production of exopolysaccharide (eps) was shown to be required for the infection process by rhizobia that induce the formation of indeterminate nodules on the roots of leguminous host plants. in sinorhizobium meliloti (also known as rhizobium meliloti) rm41, a capsular polysaccharide (kps) analogous to the group ii k antigens of escherichia coli can replace eps during symbiotic nodule development and serve as an attachment site for the strain-specific bacteriophage phi16-3. the rkpa to -j ge ... | 1998 | 9765575 |
| hpaa mutants of xanthomonas campestris pv. vesicatoria are affected in pathogenicity but retain the ability to induce host-specific hypersensitive reaction. | xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease on pepper and tomato plants. we reported previously that the main hrp (hypersensitive reaction and pathogenicity) gene cluster in x. c. pv. vesicatoria contains six transcription units, designated hrpa to hrpf. we present here the sequence of the hrpd operon and an analysis of non-polar mutants in each of the six genes. three genes, hrcq, hrcr and hrcs, are predicted to encode conserved components of type iii pr ... | 1998 | 9781876 |
| the yersinia deadly kiss. | 1998 | 9791096 | |
| endochitinase is transported to the extracellular milieu by the eps-encoded general secretory pathway of vibrio cholerae. | the chia gene of vibrio cholerae encodes a polypeptide which degrades chitin, a homopolymer of n-acetylglucosamine (glcnac) found in cell walls of fungi and in the integuments of insects and crustaceans. chia has a coding capacity corresponding to a polypeptide of 846 amino acids having a predicted molecular mass of 88.7 kda. a 52-bp region with promoter activity was found immediately upstream of the chia open reading frame. insertional inactivation of the chromosomal copy of the gene confirmed ... | 1998 | 9791107 |
| the phenolic recognition profiles of the agrobacterium tumefaciens vira protein are broadened by a high level of the sugar binding protein chve. | the formation of crown gall tumors by agrobacterium tumefaciens requires that the virulence (vir) genes be induced by chemical signals which consist of specific phenolic compounds and monosaccharides, synthesized at plant wound sites. signal transduction in the activation of these genes is mediated by the vira-virg two-component regulatory system, together with chve, a glucose-galactose binding protein which interacts with vira. we have previously presented genetic evidence that vira senses phen ... | 1998 | 9791112 |
| a metalloprotease from xanthomonas campestris that specifically degrades proline/hydroxyproline-rich glycoproteins of the plant extracellular matrix. | culture supernatants of xanthomonas campestris pv. campestris contain an enzymic activity capable of degrading gp120, a proline-rich glycoprotein associated with the extracellular matrix of the vascular bundles in petioles of turnip (brassica campestris). this activity did not reside in any of the three previously characterized proteases of x. campestris pv. campestris that were identified by their action against the model substrate beta-casein. the novel enzyme was purified by ion-exchange and ... | 1998 | 9805395 |
| localized changes in peroxidase activity accompany hydrogen peroxide generation during the development of a nonhost hypersensitive reaction in lettuce | peroxidase activity was characterized in lettuce (lactuca sativa l.) leaf tissue. changes in the activity and distribution of the enzyme were examined during the development of a nonhost hypersensitive reaction (hr) induced by pseudomonas syringae (p. s.) pv phaseolicola and in response to an hrp mutant of the bacterium. assays of activity in tissue extracts revealed ph optima of 4.5, 6.0, 5.5 to 6.0, and 6.0 to 6.5 for the substrates tetramethylbenzidine, guaiacol, caffeic acid, and chlorogenic ... | 1998 | 9808752 |
| adherence of the gram-positive bacterium ruminococcus albus to cellulose and identification of a novel form of cellulose-binding protein which belongs to the pil family of proteins. | the adherence of ruminococcus albus 8 to crystalline cellulose was studied, and an affinity-based assay was also used to identify candidate cellulose-binding protein(s). bacterial adherence in cellulose-binding assays was significantly increased by the inclusion of either ruminal fluid or micromolar concentrations of both phenylacetic and phenylpropionic acids in the growth medium, and the addition of carboxymethylcellulose (cmc) to assays decreased the adherence of the bacterium to cellulose. a ... | 1998 | 9811650 |
| the type iv leader peptidase/n-methyltransferase of vibrio vulnificus controls factors required for adherence to hep-2 cells and virulence in iron-overloaded mice. | vibrio vulnificus expresses a number of potential virulence determinants that may contribute to its ability to cause a severe and rapidly disseminating septicemia in susceptible hosts. we have cloned and characterized two genes encoding products related to components of the type iv pilus biogenesis and general secretory (type ii) pathways by complementation of a type iv peptidase/n-methyltransferase (pild) mutant of pseudomonas aeruginosa with a v. vulnificus genomic library. one of the genes (v ... | 1998 | 9826339 |
| assessment of changes in microbial community structure during operation of an ammonia biofilter with molecular tools. | biofiltration has been used for two decades to remove odors and various volatile organic and inorganic compounds in contaminated off-gas streams. although biofiltration is widely practiced, there have been few studies of the bacteria responsible for the removal of air contaminants in biofilters. in this study, molecular techniques were used to identify bacteria in a laboratory-scale ammonia biofilter. both 16s rrna and ammonia monooxygenase (amoa) genes were used to characterize the heterotrophi ... | 1998 | 9835577 |
| sinorhizobium fredii and sinorhizobium meliloti produce structurally conserved lipopolysaccharides and strain-specific k antigens. | lipopolysaccharides (lps) and capsular polysaccharides (k antigens) may influence the interaction of rhizobia with their specific hosts; therefore, we conducted a comparative analysis of sinorhizobium fredii and sinorhizobium meliloti, which are genetically related, yet symbiotically distinct, nitrogen-fixing microsymbionts of legumes. we found that both species typically produce strain-specific k antigens that consist of 3-deoxy-d-manno-2-octulosonic acid (kdo), or other 1-carboxy-2-keto-3-deox ... | 1998 | 9835585 |
| the virulence plasmid of yersinia, an antihost genome. | the 70-kb virulence plasmid enables yersinia spp. (yersinia pestis, y. pseudotuberculosis, and y. enterocolitica) to survive and multiply in the lymphoid tissues of their host. it encodes the yop virulon, an integrated system allowing extracellular bacteria to disarm the cells involved in the immune response, to disrupt their communications, or even to induce their apoptosis by the injection of bacterial effector proteins. this system consists of the yop proteins and their dedicated type iii sec ... | 1998 | 9841674 |
| the arabidopsis thaliana rpm1 disease resistance gene product is a peripheral plasma membrane protein that is degraded coincident with the hypersensitive response. | disease resistance in plants is often controlled by a gene-for-gene mechanism in which avirulence (avr) gene products encoded by pathogens are specifically recognized, either directly or indirectly, by plant disease resistance (r) gene products. members of the nbs-lrr class of r genes encode proteins containing a putative nucleotide binding site (nbs) and carboxyl-terminal leucine-rich repeats (lrrs). generally, nbs-lrr proteins do not contain predicted transmembrane segments or signal peptides, ... | 1998 | 9861059 |
| the ecs1 gene of arabidopsis encodes a plant cell wall-associated protein and is potentially linked to a locus influencing resistance to xanthomonas campestris. | the interaction between arabidopsis and xanthomonas campestris pv. campestris (xcc) provides a useful model system to identify components that are involved in incompatible interactions of this phytopathogen and cruciferous plants. we have previously described a new gene from arabidopsis thaliana, ecs1 (formerly cxc750), which showed an ecotype-specific expression pattern, although homologous sequences are present in the genomes of all ecotypes tested. interestingly, ecs1 mrna transcripts were on ... | 1998 | 9869403 |
| effect of oxidative stress on the biosynthesis of 2-c-methyl-d-erythritol-2,4-cyclopyrophosphate and isoprenoids by several bacterial strains. | in this study, the gram-negative bacteria xanthomonas campestris, xanthomonas maltophilia, and pseudomonas putida, facultative parasites of plants and animals, were shown to accumulate 2-c-methyl-d-erythritol-2,4-cyclopyrophosphate (mec) in response to benzyl-viologen-induced oxidative stress. corynebacterium ammoniagenes mutants capable of accumulating mec in the absence of an exogenous oxidative stress inducer were obtained. isoprenoid synthesis and mec synthesis in these and other bacteria we ... | 1998 | 9871022 |
| intracellular compounds quantification by means of flow cytometry in bacteria: application to xanthan production by xanthomonas campestris. | the use of flow cytometry (fcm) to quantitatively analyze intracellular compounds is studied. fcm is a very useful technique for individual cell studies in microbial systems, and gives access to information which cannot be obtained in any other way. nevertheless, it provides data in arbitrary units, that is, relative data. this analytical technique could be employed for kinetic modeling of microbial systems and even for internal phenomena analysis, but for this purpose, absolute data-that is con ... | 1998 | 10099182 |
| oxygen supply without gas-liquid film resistance to xanthomonas campestris cultivation | alternative methods of oxygen supply are of crucial importance, especially in viscous fermentations and shear-sensitive fermentations. a method of oxygen supply that completely eliminates the gas-liquid transport resistance has been presented. the method involves a need-based liquid-phase decomposition of hydrogen peroxide to provide the necessary oxygen. when xanthomonas campestris was cultivated (viscous cultivation) using this method of oxygen supply, dissolved oxygen (do) levels were maintai ... | 1998 | 10099392 |
| 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 |