| gene transfer by transduction in the marine environment. | to determine the potential for bacteriophage-mediated gene transfer in the marine environment, we established transduction systems by using marine phage host isolates. plasmid pqsr50, which contains transposon tn5 and encodes kanamycin and streptomycin resistance, was used in plasmid transduction assays. both marine bacterial isolates and concentrated natural bacterial communities were used as recipients in transduction studies. transductants were detected by a gene probe complementary to the ne ... | 1998 | 9687430 |
| 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 |
| 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 |
| genetic analysis of hrp-related dna sequences of xanthomonas campestris strains causing diseases of citrus. | the hrp gene cluster of strains of xanthomonas campestris that cause diseases of citrus was examined by southern hybridization of genomic dna and by restriction endonuclease analysis of enzymatically amplified dna fragments of the hrp gene cluster. the hrp genes were present in all strains of the pathovars of x. campestris tested in this study, including strains of the three aggressiveness groups of the citrus bacterial spot pathogen, x. campestris pv. citrumelo. x. campestris pv. citri strains ... | 1994 | 7912499 |
| 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 |
| molecular mechanisms of copper resistance and accumulation in bacteria. | an unusual mechanism of metal resistance is found in certain plant pathogenic strains of pseudomonas syringae that are exposed to high levels of copper compounds used in disease control on agricultural crops. these bacteria accumulate blue cu2+ ions in the periplasm and outer membrane. at least part of this copper sequestering activity is determined by copper-binding protein products of the copper resistance operon (cop). potential copper-binding sites of the periplasmic copa protein show conser ... | 1994 | 7917425 |
| 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 |
| defense-related gene induction in brassica campestris in response to defined mutants of xanthomonas campestris with altered pathogenicity. | we have studied the induction of beta-1,3-glucanase (bgl) in turnip following inoculation with pathovars of xanthomonas campestris and derived mutants. bgl transcript accumulated more rapidly in leaves in the incompatible interactions with x. c. pv. armoraciae and x. c. pv. raphani than in the compatible interaction with x. c. pv. campestris. no accumulation was seen in response to wounding or inoculation with water, salicylic acid, or escherichia coli. deletion of the hrp cluster from the x. ca ... | 1994 | 7949324 |
| use of whey for production of exocellular polysaccharide by a mutant strain of xanthomonas campestris. | growth and kinetics of the production of exocellular polysaccharide was studied in a mutant strain of xanthomonas campestris lac+ during cultivation in a submerged culture in a medium containing whey. the maximum production of the polymer was observed at the initial stage of the stationary growth phase of the culture. the mean production yield was about 1.4%. the results were comparable with those obtained during cultivation on a lactose medium. | 1992 | 1505865 |
| 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 |
| a new protein subunit k for rna polymerase from xanthomonas campestris pv. oryzae. | during the purification of rna polymerase from xanthomonas campestris pv. oryzae, a new subunit named k was found to be associated with this enzyme. the removal of subunit k from holoenzyme by deae-cellulose column chromatography results in a decrease in specific activity of the enzyme. the readdition of subunit k to subunit k-depleted holoenzyme results in restoration of enzymatic activity. subunit k increase the activity of rna polymerase; the activation was in proportion to the concentration ... | 1989 | 2647734 |
| 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 |
| chromosome map of xanthomonas campestris pv. campestris 17 with locations of genes involved in xanthan gum synthesis and yellow pigmentation. | no plasmid was detected in xanthomonas campestris pv. campestris 17, a strain of the causative agent of black rot in cruciferous plants isolated in taiwan. its chromosome was cut by paci, pmei, and swai into five, two, and six fragments, respectively, and a size of 4.8 mb was estimated by summing the fragment lengths in these digests. based on the data obtained from partial digestion and southern hybridization using probes common to pairs of the overlapping fragments or prepared from linking fra ... | 1999 | 9864320 |
| analysis of pectate lyases produced by soft rot bacteria associated with spoilage of vegetables. | isoelectric focusing (ief) profiles of pectate lyases (pls) produced by five different groups of soft rot bacteria were analyzed by using the combined techniques of thin-layer polyacrylamide gel ief and agarose-pectate overlay activity staining. four strains of soft rot erwinia spp. produced three or more pl isozymes. all of eight pseudomonas viridiflava strains examined produced one single pl with a pi of 9.7. all 10 of pseudomonas fluorescens strains produced two pls; the major one had a pi of ... | 1989 | 2764574 |
| minimal region necessary for autonomous replication of ptar. | the native 44-kilobase-pair plasmid ptar, discovered in a grapevine strain of agrobacterium tumefaciens, contains a single origin of dna replication confined to a 1.0-kilobase-pair region of the macromolecule. this region (ori) confers functions sufficient for replication in agrobacterium and rhizobium species but not in pseudomonas solanacearum, pseudomonas glumae, pseudomonas syringae pv. savastanoi, xanthomonas campestris pv. campestris, and escherichia coli. ori contains a repa gene that enc ... | 1988 | 3290199 |
| 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 |
| new mobilizable vectors suitable for gene replacement in gram-negative bacteria and their use in mapping of the 3' end of the xanthomonas campestris pv. campestris gum operon. | we describe useful vectors to select double-crossover events directly in site-directed marker exchange mutagenesis in gram-negative bacteria. these vectors contain the gusa marker gene, providing colorimetric screens to identify bacteria harboring those sequences. the applicability of these vectors was shown by mapping the 3' end of the xanthomonas campestris gum operon, involved in biosynthesis of xanthan. | 1999 | 9872790 |
| overexpression of pto activates defense responses and confers broad resistance. | the tomato disease resistance (r) gene pto specifies race-specific resistance to the bacterial pathogen pseudomonas syringae pv tomato carrying the avrpto gene. pto encodes a serine/threonine protein kinase that is postulated to be activated by a physical interaction with the avrpto protein. here, we report that overexpression of pto in tomato activates defense responses in the absence of the pto-avrpto interaction. leaves of three transgenic tomato lines carrying the cauliflower mosaic virus 35 ... | 1999 | 9878629 |
| regulation of expression of avirulence gene avrrxv and identification of a family of host interaction factors by sequence analysis of avrbst. | resistance in tomato line hawaii 7998 as well as in several nonhost plants to xanthomonas campestris pv. vesicatoria tomato strain (xcvt) is mediated in part by the avirulence gene avrrxv. analysis of growth of wild-type and avrrxv deletion strains indicates that avrrxv plays a crucial role in the ability of xcvt 92-14 to induce resistance on hawaii 7998. we used avrrxv reporter gene fusions and northern (rna) blot analysis to test several growth environments for inductive potential. we found th ... | 1999 | 9885191 |
| bacterial leaf spot of zinnia elegans, a new disease in argentina. | a bacterial disease of zinnia elegans (compositae), caused by xanthomonas campestris pv. zinniae is recorded for the first time in argentina. the identification of the causal organism was based on disease symptoms, pathogenicity and morphological and physiological characteristics of the cultures isolated from material collected at la plata, province of buenos aires, argentina. | 1985 | 3916667 |
| sequence and function of luxu: a two-component phosphorelay protein that regulates quorum sensing in vibrio harveyi. | vibrio harveyi regulates the expression of bioluminescence (lux) in response to cell density, a phenomenon known as quorum sensing. in v. harveyi, two independent quorum-sensing systems exist, and each produces, detects, and responds to a specific cell density-dependent autoinducer signal. the autoinducers are recognized by two-component hybrid sensor kinases called luxn and luxq, and sensory information from both systems is transduced by a phosphorelay mechanism to the response regulator protei ... | 1999 | 9922254 |
| noll of rhizobium sp. strain ngr234 is required for o-acetyltransferase activity. | following (iso)flavonoid induction, nodulation genes of the symbiotic nitrogen-fixing bacterium rhizobium sp. strain ngr234 elaborate a large family of lipooligosaccharidic nod factors (nodngr factors). when secreted into the rhizosphere of compatible legumes, these signal molecules initiate root hair deformation and nodule development. the nonreducing glucosamine residue of nodngr factors are n acylated, n methylated, and mono- or biscarbamoylated, while position c-6 of the reducing extremity i ... | 1999 | 9922261 |
| cell-specific production and antimicrobial activity of naphthoquinones in roots of lithospermum erythrorhizon | pigmented naphthoquinone derivatives of shikonin are produced at specific times and in specific cells of lithospermum erythrorhizon roots. normal pigment development is limited to root hairs and root border cells in hairy roots grown on "noninducing" medium, whereas induction of additional pigment production by abiotic (cuso4) or biotic (fungal elicitor) factors increases the amount of total pigment, changes the ratios of derivatives produced, and initiates production of pigment de novo in epide ... | 1999 | 9952436 |
| copper-binding characteristics of exopolymers from a freshwater-sediment bacterium. | copper-binding activity by exopolymers from adherent cells of a freshwater-sediment bacterium was demonstrated by a combination of equilibrium dialysis and flameless atomic absorption spectrometry. crude, cell-free exopolymer preparations containing protein and polysaccharide components bound up to 37 nmol of cu per mg (dry weight). a highly purified exopolysaccharide preparation bound up to 253 nmol of cu per mg of carbohydrate. the conditional stability constant for the crude exopolymer-cu com ... | 1985 | 4004217 |
| characterization of insertions of is476 and two newly identified insertion sequences, is1478 and is1479, in xanthomonas campestris pv. campestris. | thirty-two plasmid insertion mutants were independently isolated from two strains of xanthomonas campestris pv. campestris in taiwan. of the 32 mutants, 14 (44%), 8 (25%), and 4 (12%) mutants resulted from separate insertions of an is3 family member, is476, and two new insertion sequences (is), is1478 and is1479. while is1478 does not have significant sequence homology with any is elements in the embl/genbank/ddbj database, is1479 demonstrated 73% sequence homology with is1051 in x. campestris p ... | 1999 | 9973349 |
| prhj and hrpg, two new components of the plant signal-dependent regulatory cascade controlled by prha in ralstonia solanacearum. | hrp gene expression in the phytopathogenic bacterium ralstonia solanacearum gmi1000 is induced through the hrpb regulator in minimal medium and upon co-culture with plant cell suspensions. the putative outer membrane protein prha is specifically involved in hrp gene activation in the presence of plant cells and has been proposed to be a receptor of a plant-dependent signal transduction pathway. here, we report on the identification of two regulatory genes, hrpg and prhj, located at the right-han ... | 1999 | 9987125 |
| suppression of bacterial blight by a bacterial community isolated from the guttation fluids of anthuriums | growth and survival of xanthomonas campestris pv. dieffenbachiae in guttation fluids (xylem sap exuded from leaf margins) of anthuriums were suppressed by several bacterial strains indigenous to leaves of various anthurium cultivars. inhibition of growth was not observed in filter-sterilized guttation fluids and was restored to original levels only by reintroducing specific mixtures of bacteria into filter-sterilized guttation fluids. the inhibitory effect was related to the species in the bacte ... | 1999 | 10049858 |
| isolation of ethylene-insensitive soybean mutants that are altered in pathogen susceptibility and gene-for-gene disease resistance | plants commonly respond to pathogen infection by increasing ethylene production, but it is not clear if this ethylene does more to promote disease susceptibility or disease resistance. ethylene production and/or responsiveness can be altered by genetic manipulation. the present study used mutagenesis to identify soybean (glycine max l. merr.) lines with reduced sensitivity to ethylene. two new genetic loci were identified, etr1 and etr2. mutants were compared with isogenic wild-type parents for ... | 1999 | 10069832 |
| the sinorhizobium meliloti insertion sequence (is) elements isrm102f34-1/isrm7 and isrm220-13-5 belong to a new family of insertion sequence elements. | the sinorhizobium meliloti insertion sequence (is) elements isrm102f34-1 and isrm220-13-5 are 1481 and 1550 base pairs (bp) in size, respectively. isrm102f34-1 is bordered by 15 bp imperfect terminal inverted repeat sequences (two mismatches), whereas the terminal inverted repeat of isrm220-13-5 has a length of 16 bp (two mismatches). both insertion sequence elements generate a 6-bp target duplication upon transposition. the putative transposase enzymes of isrm102f34-1 and isrm220-13-5 consist o ... | 1999 | 10079521 |
| mutational analysis of the vaca promoter provides insight into gene transcription in helicobacter pylori. | analysis of 12 helicobacter pylori promoters indicates the existence of a consensus -10 hexamer (tataat) but little conservation of -35 sequences. in this study, mutations in either the h. pylori vaca -10 region or the -35 region resulted in decreased vaca transcription and suggested that an extended -10 motif is utilized. thus, despite the lack of a -35 consensus sequence for h. pylori promoters, the -35 region plays a functional role in vaca transcription. | 1999 | 10094707 |
| cellular locations of pseudomonas syringae pv. syringae hrcc and hrcj proteins, required for harpin secretion via the type iii pathway. | the complete hrp-hrc-hrma cluster of pseudomonas syringae pv. syringae 61 encodes 28 polypeptides. a saprophytic bacterium carrying this cluster is capable of secreting hrpz-a harpin encoded by hrpz-in an hrp-dependent manner, which suggests that this cluster contains sufficient components to assemble functional type iii secretion machinery. sequence data show that hrcj and hrcc are putative outer membrane proteins, and nonpolar mutagenesis demonstrates they are all required for hrpz secretion. ... | 1999 | 10094714 |
| vibrio cholerae o1 el tor: identification of a gene cluster required for the rugose colony type, exopolysaccharide production, chlorine resistance, and biofilm formation. | the rugose colony variant of vibrio cholerae o1, biotype el tor, is shown to produce an exopolysaccharide, epsetr, that confers chlorine resistance and biofilm-forming capacity. epsetr production requires a chromosomal locus, vps, that contains sequences homologous to carbohydrate biosynthesis genes of other bacterial species. mutations within this locus yield chlorine-sensitive, smooth colony variants that are biofilm deficient. the biofilm-forming properties of epsetr may enable the survival o ... | 1999 | 10097157 |
| 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 |
| location and survival of leaf-associated bacteria in relation to pathogenicity and potential for growth within the leaf | the growth and survival of pathogenic and nonpathogenic pseudomonas syringae strains and of the nonpathogenic species pantoea agglomerans, stenotrophomonas maltophilia, and methylobacterium organophilum were compared in the phyllosphere of bean. in general, the plant pathogens survived better than the nonpathogens on leaves under environmental stress. the sizes of the total leaf-associated populations of the pathogenic p. syringae strains were greater than the sizes of the total leaf-associated ... | 1999 | 10103233 |
| cuma, a gene encoding a multicopper oxidase, is involved in mn2+ oxidation in pseudomonas putida gb-1. | pseudomonas putida gb-1-002 catalyzes the oxidation of mn2+. nucleotide sequence analysis of the transposon insertion site of a nonoxidizing mutant revealed a gene (designated cuma) encoding a protein homologous to multicopper oxidases. addition of cu2+ increased the mn2+-oxidizing activity of the p. putida wild type by a factor of approximately 5. the growth rates of the wild type and the mutant were not affected by added cu2+. a second open reading frame (designated cumb) is located downstream ... | 1999 | 10103278 |
| transcription of the genome of the filamentous bacteriophage cf from both plus and minus dna strands. | the filamentous bacteriophage cf infects the bacterium xanthomonas campestris pv. citri. northern blot analysis with probes derived from various restriction fragments of cf replicative form (rf) dna has revealed the presence of five major phage-specific transcripts in infected cells. four of these transcripts were shown to be derived from the region of the cf genome extending from gene ii to gene viii and are consistent with the cascade model of transcription proposed for ff coliphages. these tr ... | 1999 | 10191188 |
| azospirillum irakense produces a novel type of pectate lyase. | the pela gene from the n2-fixing plant-associated bacterium azospirillum irakense, encoding a pectate lyase, was isolated by heterologous expression in escherichia coli. nucleotide sequence analysis of the region containing pela indicated an open reading frame of 1,296 bp, coding for a preprotein of 432 amino acids with a typical amino-terminal signal peptide of 24 amino acids. n-terminal amino acid sequencing confirmed the processing of the protein in e. coli at the signal peptidase cleavage si ... | 1999 | 10198006 |
| the adsorption protein genes of xanthomonas campestris filamentous phages determining host specificity. | gene iii (giii) of philf, a filamentous phage specifically infecting xanthomonas campestris pv. campestris, was previously shown to encode a virion-associated protein (piii) required for phage adsorption. in this study, the transcription start site for the gene and the n-terminal sequence of the protein were determined, resulting in the revision of the translation initiation site from the one previously predicted for this gene. for comparative study, the giii of phixv, a filamentous phage specif ... | 1999 | 10198010 |
| characterization of two novel type i ribosome-inactivating proteins from the storage roots of the andean crop mirabilis expansa. | two novel type i ribosome-inactivating proteins (rips) were found in the storage roots of mirabilis expansa, an underutilized andean root crop. the two rips, named me1 and me2, were purified to homogeneity by ammonium sulfate precipitation, cation-exchange perfusion chromatography, and c4 reverse-phase chromatography. the two proteins were found to be similar in size (27 and 27.5 kd) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their isoelectric points were determined to be ... | 1999 | 10198104 |
| genetic diversity of african and worldwide strains of ralstonia solanacearum as determined by pcr-restriction fragment length polymorphism analysis of the hrp gene region | the genetic diversity among a worldwide collection of 120 strains of ralstonia solanacearum was assessed by restriction fragment length polymorphism (rflp) analysis of amplified fragments from the hrp gene region. five amplified fragments appeared to be specific to r. solanacearum. fifteen different profiles were identified among the 120 bacterial strains, and a hierarchical cluster analysis distributed them into eight clusters. each cluster included strains belonging to a single biovar, except ... | 1999 | 10224018 |
| molecular characterization of a flagellar export locus of helicobacter pylori. | motility of helicobacter species has been shown to be essential for successful colonization of the host. we have investigated the organization of a flagellar export locus in helicobacter pylori. a 7-kb fragment of the h. pylori ccug 17874 genome was cloned and sequenced, revealing an operon comprising an open reading frame of unknown function (orf03), essential housekeeping genes (iles and murb), flagellar export genes (flii and fliq), and a homolog to a gene implicated in virulence factor trans ... | 1999 | 10225855 |
| direct interaction of the epsl and epsm proteins of the general secretion apparatus in vibrio cholerae. | the general secretion pathway of gram-negative bacteria is responsible for extracellular secretion of a number of different proteins, including proteases and toxins. this pathway supports secretion of proteins across the cell envelope in two distinct steps, in which the second step, involving translocation through the outer membrane, is assisted by at least 13 different gene products. two of these components, the cytoplasmic membrane proteins epsl and epsm of vibrio cholerae, have been purified ... | 1999 | 10322014 |
| molecular characterization of a brucella species large dna fragment deleted in brucella abortus strains: evidence for a locus involved in the synthesis of a polysaccharide. | a brucella melitensis 16m dna fragment of 17,119 bp, which contains a large region deleted in b. abortus strains and dna flanking one side of the deletion, has been characterized. in addition to the previously identified omp31 gene, 14 hypothetical genes have been identified in the b. melitensis fragment, most of them showing homology to genes involved in the synthesis of a polysaccharide. considering that 10 of the 15 genes are missing in b. abortus and that all the polysaccharides described in ... | 1999 | 10338472 |
| quantitative immunofluorescence of regulated eps gene expression in single cells of ralstonia solanacearum. | ralstonia solanacearum, a phytopathogenic bacterium, uses an environmentally sensitive and complex regulatory network to control expression of multiple virulence genes. part of this network is an unusual autoregulatory system that produces and senses 3-hydroxypalmitic acid methyl ester. in culture, this autoregulatory system ensures that expression of virulence genes, such as those of the eps operon encoding biosynthesis of the acidic extracellular polysaccharide, occurs only at high cell densit ... | 1999 | 10347013 |
| conformation of the extracellular polysaccharide of xanthomonas campestris. | the solution conformation of the extracellular polysaccharide of the bacterium xanthomonas campestris is examined by optical rotation, viscometry, and potentiometric titration. measurements of optical rotation vs. temperature for solutions of the polysaccharide at low ionic strength reveal a sharp transition to a denatured structure which is reversible if sufficient salt is present. the temperature tm at the transition midpoint increases as log (na+) or log (ca2+). viscosity-temperature profiles ... | 1976 | 9135 |
| structures and properties of gellan polymers produced by sphingomonas paucimobilis atcc 31461 from lactose compared with those produced from glucose and from cheese whey | the dairy industry produces large quantities of whey as a by-product of cheese production and is increasingly looking for new ways to utilize this waste product. gellan gum is reliably produced by sphingomonas paucimobilis in growth media containing lactose, a significant component of cheese whey, as a carbon source. we studied and compared polysaccharide biosynthesis by s. paucimobilis atcc 31461 in media containing glucose, lactose (5 to 30 g/liter), and sweet cheese whey. we found that alteri ... | 1999 | 10347031 |
| microbial system for polysaccharide depolymerization: enzymatic route for xanthan depolymerization by bacillus sp. strain gl1. | an enzymatic route for the depolymerization of a heteropolysaccharide (xanthan) in bacillus sp. strain gl1, which was closely related to brevibacillus thermoruber, was determined by analyzing the structures of xanthan depolymerization products. the bacterium produces extracellular xanthan lyase catalyzing the cleavage of the glycosidic bond between pyruvylated mannosyl and glucuronyl residues in xanthan side chains (w. hashimoto et al., appl. environ. microbiol. 64:3765-3768, 1998). the modified ... | 1999 | 10347037 |
| effect of the nitrogen source on pyruvate content and rheological properties of xanthan | batch and fed batch cultivations of xanthomonas campestris with varying amounts of the n source (nh4cl) yield xanthan polymers which differ in pyruvate content. analyzing the rheological properties of the xanthans produced exhibits that it is not only the molecular mass but also the pyruvate content that affects the viscosity of xanthan solutions. however, there is obviously no simple functional dependency but rather a step increase in viscosity when going from below 2 to above 3 wt % of pyruvat ... | 1999 | 10356261 |
| pseudomonas syringae phytotoxins: mode of action, regulation, and biosynthesis by peptide and polyketide synthetases. | coronatine, syringomycin, syringopeptin, tabtoxin, and phaseolotoxin are the most intensively studied phytotoxins of pseudomonas syringae, and each contributes significantly to bacterial virulence in plants. coronatine functions partly as a mimic of methyl jasmonate, a hormone synthesized by plants undergoing biological stress. syringomycin and syringopeptin form pores in plasma membranes, a process that leads to electrolyte leakage. tabtoxin and phaseolotoxin are strongly antimicrobial and func ... | 1999 | 10357851 |
| genome size and macrorestriction map of xanthomonas campestris pv. glycines yr32 chromosome. | xanthomonas campestris is an important plant pathogenic bacterium which causes severe diseases in a wide variety of plant species. we have generated a macrorestriction map of the x. campestris (axonopodis) pv. glycines chromosome employing pulsed-field gel electrophoresis (pfge). restriction endonucleases paci (5'-ttaattaa), pmei (5'-gtttaaac) and swai (5'-atttaaat) digested the chromosomal dna into three, five, and five fragments, respectively. in addition, intron-encoded restriction endonuclea ... | 1999 | 10361709 |
| enhanced expression and activation of the alternative oxidase during infection of arabidopsis with pseudomonas syringae pv tomato. | cyanide-resistant ("alternative") respiration was studied in arabidopsis during incompatible and compatible infection with pseudomonas syringae pv tomato dc3000. total leaf respiration increased as the leaves became necrotic, as did the cyanide-resistant component that was sensitive to salicylhydroxamic acid. infiltration of leaves with an avirulent strain rapidly induced alternative oxidase (aox) mrna, whereas the increase was delayed in the compatible combination. the increase in mrna correlat ... | 1999 | 10364404 |
| the mdoc gene of escherichia coli encodes a membrane protein that is required for succinylation of osmoregulated periplasmic glucans. | osmoregulated periplasmic glucans (opgs) of escherichia coli are anionic oligosaccharides that accumulate in the periplasmic space in response to low osmolarity of the medium. their anionic character is provided by the substitution of the glucosidic backbone by phosphoglycerol originating from the membrane phospholipids and by succinyl residues from unknown origin. a phosphoglycerol-transferase-deficient mdob mutant was subjected to tn5 transposon mutagenesis, and putative mutant clones were scr ... | 1999 | 10368134 |
| [microbiological synthesis of virazole by immobilized cells]. | based on the isotherms of adsorption of the cells of xanthomonas campestris b-610 to glass and polyvinyl fibers, immobilized systems were produced, in which the cell content was sufficient for enzymatic synthesis of virazole (1-[beta-d-ribofuranosyl]-1,2,4-triazole-3-carboxamide) using adenosine as a donor of ribose (50-60% conversion of 1,2,4-triazole-3-carboxamide). the immobilized cells thus obtained retain their enzymatic activity for six months and can be used repeatedly. | 1999 | 10368847 |
| ribonucleotide reduction in pseudomonas species: simultaneous presence of active enzymes from different classes. | three separate classes of ribonucleotide reductases exist in nature. they differ widely in protein structure. class i enzymes are found in aerobic bacteria and eukaryotes; class ii enzymes are found in aerobic and anaerobic bacteria; class iii enzymes are found in strict and facultative anaerobic bacteria. usually, but not always, one organism contains only one or two (in facultative anaerobes) classes. surprisingly, the genomic sequence of pseudomonas aeruginosa contains sequences for each of t ... | 1999 | 10383965 |
| 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 |
| molecular cloning and characterization of a locus responsible for o acetylation of the o polysaccharide of legionella pneumophila serogroup 1 lipopolysaccharide. | complementation experiments, tn5 mutagenesis, and dna sequencing were used to identify a locus (lag-1) that participates in acetylation of legionella pneumophila serogroup 1 lipopolysaccharide. nuclear magnetic resonance analyses of lipopolysaccharides from mutant and complemented strains suggest that lag-1 is responsible for o acetylation of serogroup 1 o polysaccharide. | 1999 | 10383989 |
| 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 |
| identification of a novel beta-lactamase produced by xanthomonas campestris, a phytopathogenic bacterium. | the xanthomonas campestris pv. campestris 11 chromosome encodes a periplasmic beta-lactamase of 30 kda. gene replacement and complementation confirmed the presence of this enzyme. its deduced amino acid sequence shows identity and conserved domains between it and stenotrophomonas maltophilia l2 and other ambler class a/bush group 2 beta-lactamases. southern hybridization detected a single homologous fragment in each of 12 other xanthomonas strains, indicating that the presence of a beta-lactamas ... | 1999 | 10390247 |
| characterization of is1389, a new member of the is3 family of insertion sequences isolated from xanthomonas campestris pv. amaranthicola. | is1389, a new insertion sequence belonging to the is3 family, has been identified in xanthomonas campestris pv. amaranthicola. the genome of this bacterium contains at least 11 copies of the element, whereas no hybridizing sequences were detected in other xanthomonas species [x. axonopodis, x. fragaridae, x. phaseoli, and x. (stenotrophomonas) maltophila]. two nearly identical copies of the element (is1389-a and is1389-b) were characterized. according to analysis of sequence alignments and simil ... | 1999 | 10398747 |
| specific detection of xylella fastidiosa pierce's disease strains. | pierce's disease (pd, xylella fastidiosa) of grapevine is the primary pathogen limiting vinifera grape production in florida and other regions of the southeastern united states. quick and accurate detection of pd strains is essential for pd studies and control. a unique random amplified polymorphic dna (pd1-1-2) was isolated from a pd strain from florida. fragment pd1-1-2 was cloned, sequenced, and found to be 1005 bp in length. pcr primers were designed to utilize these sequence data for pd str ... | 1999 | 10398832 |
| the genes ruba and rubb for alkane degradation in acinetobacter sp. strain adp1 are in an operon with estb, encoding an esterase, and oxyr. | alkanes are oxidized in acinetobacter sp. strain adp1 by a three-component alkane monooxygenase, composed of alkane hydroxylase, rubredoxin, and rubredoxin reductase. ruba and rubb encode rubredoxin and a nad(p)h-dependent rubredoxin reductase. we demonstrate here that single base pair substitutions in ruba or rubb lead to defects in alkane degradation, showing that both genes are essential for alkane utilization. differences in the degradation capacity for hexadecane and dodecane in these mutan ... | 1999 | 10400587 |
| 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 |
| influence of soft rot bacteria on growth of listeria monocytogenes on potato tuber slices. | growth of listeria monocytogenes on potato tuber slices and its interaction with four representative species of soft rot bacteria (pseudomonas fluorescens, p. viridiflava, erwinia carotovora subsp. carotovora, and xanthomonas campestris) were investigated. when potato tuber slices were inoculated with one of two l. monocytogenes strains (scott a and atcc 15313), an increase in numbers of 3 to 4 logs per gram of tissue was observed with samples that were stored at 20 degrees c for 6 days. however ... | 1999 | 10419206 |
| community analysis of biofilters using fluorescence in situ hybridization including a new probe for the xanthomonas branch of the class proteobacteria. | domain-, class-, and subclass-specific rrna-targeted probes were applied to investigate the microbial communities of three industrial and three laboratory-scale biofilters. the set of probes also included a new probe (named xan818) specific for the xanthomonas branch of the class proteobacteria; this probe is described in this study. the members of the xanthomonas branch do not hybridize with previously developed rrna-targeted oligonucleotide probes for the alpha-, beta-, and gamma-proteobacteri ... | 1999 | 10427047 |
| a high-density physical map of sinorhizobium meliloti 1021 chromosome derived from bacterial artificial chromosome library. | as part of the european sinorhizobium meliloti (strain 1021) chromosome sequencing project, four genomic bacterial artificial chromosome (bac) libraries have been constructed, one of which was mainly used for chromosome mapping. this library consists of 1,824 clones with an average insert size of 80 kilobases and represents approximately 20-fold total genome coverage [6.8 megabases (mbs)]. pcr screening of 384 bac clones with 447 chromosomal markers (pcr primer pairs), consisting of 73 markers r ... | 1999 | 10430947 |
| the xanthomonas hrp type iii system secretes proteins from plant and mammalian bacterial pathogens. | studies of essential pathogenicity determinants in gram-negative bacteria have revealed the conservation of type iii protein secretion systems that allow delivery of virulence factors into host cells from plant and animal pathogens. ten of 21 hrp proteins of the plant pathogen xanthomonas campestris pv. vesicatoria have been suggested to be part of a type iii machinery. here, we report the hrp-dependent secretion of two avirulence proteins, avrbs3 and avrrxv, by x. campestris pv. vesicatoria str ... | 1999 | 10430949 |
| role of the hrp type iii protein secretion system in growth of pseudomonas syringae pv. syringae b728a on host plants in the field. | hrp genes are reportedly required for pathogenicity in pseudomonas syringae pv. syringae (pss) and other phytopathogenic bacterial species. a subset of these genes encodes a type iii secretion system through which virulence factors are thought to be delivered to plant cells. in this study, we sought to better understand the role that hrp genes play in interactions of pss with its host as they occur naturally under field conditions. population sizes of hrp mutants with defects in genes that encod ... | 1999 | 10449783 |
| a simplified subtractive hybridization protocol used to isolate dna sequences specific to xylella fastidiosa. | a simplified protocol of subtractive hybridization based on the technique of l. m. kunkel, a. p. monaco, w. middlesworth, h. d. ochs & s. a. latt (1985, proc natl acad sci usa, 82, 4778-4782) was used to obtain dna sequences specific to xylella fastidiosa isolated from diseased citrus plants. as a driver, dna extracted from bacteria showing different degrees of relatedness was used: xy. fastidiosa 788 isolated from another host (plum), xanthomonas campestris pv. campestris and burkholderia gladi ... | 1999 | 10463163 |
| the 17-gene ethanolamine (eut) operon of salmonella typhimurium encodes five homologues of carboxysome shell proteins. | the eut operon of salmonella typhimurium encodes proteins involved in the cobalamin-dependent degradation of ethanolamine. previous genetic analysis revealed six eut genes that are needed for aerobic use of ethanolamine; one (eutr), encodes a positive regulator which mediates induction of the operon by vitamin b12 plus ethanolamine. the dna sequence of the eut operon included 17 genes, suggesting a more complex pathway than that revealed genetically. we have correlated an open reading frame in t ... | 1999 | 10464203 |
| characterization of transposon-generated protease mutant of xanthomonas campestris pathovar glycine 8ra. enzyme activity, cloning, and mapping of flanking dna. | protease negative mutant of xanthomonas campestris pathovar glycine 8ra (prt-mutant) was constructed by mutagenesis employing artificial transposon omegon-km. transposon delivery was conducted through diparental conjugation using x. campestris pathovar glycine 8ra as recipient and escherichia coli s17-1 carrying pjff 3500 plasmid as the donor. the frequency of transconjugation was found 1.9 x 10(-7) per recipient. enzyme analysis indicated the presence of mutant with lower protease activity than ... | 1999 | 10464767 |
| bacillus subtilis aconitase is an rna-binding protein. | the aconitase protein of bacillus subtilis was able to bind specifically to sequences resembling the iron response elements (ires) found in eukaryotic mrnas. the sequences bound include the rabbit ferritin ire and ire-like sequences in the b. subtilis operons that encode the major cytochrome oxidase and an iron uptake system. ire binding activity was affected by the availability of iron both in vivo and in vitro. in eukaryotic cells, aconitase-like proteins regulate translation and stability of ... | 1999 | 10468622 |
| expression of the isoamylase gene of flavobacterium odoratum ku in escherichia coli and identification of essential residues of the enzyme by site-directed mutagenesis. | the isoamylase gene from flavobacterium odoratum ku was cloned into and expressed in escherichia coli jm109. the promoter of the gene was successful in e. coli, and the enzyme produced was excreted into the culture medium, depending on the amount of the enzyme expressed. the enzyme found in the culture medium showed almost the same m(r), heat-inactivating constant, and n-terminal sequence as those of the enzyme accumulated in the periplasmic space. this result indicated that the enzyme accumulat ... | 1999 | 10473430 |
| development and application of pathovar-specific monoclonal antibodies that recognize the lipopolysaccharide o antigen and the type iv fimbriae of xanthomonas hyacinthi. | the objective of this study was to develop a specific immunological diagnostic assay for yellow disease in hyacinths, using monoclonal antibodies (mabs). mice were immunized with a crude cell wall preparation (shear fraction) from xanthomonas hyacinthi and with purified type iv fimbriae. hybridomas were screened for a positive reaction with x. hyacinthi cells or fimbriae and for a negative reaction with x. translucens pv. graminis or erwinia carotovora subsp. carotovora. nine mabs recognized fim ... | 1999 | 10473431 |
| an hrcu-homologous gene mutant of xanthomonas campestris pv. glycines 8ra that lost pathogenicity on the host plant but was able to elicit the hypersensitive response on nonhosts. | transposon mutagenesis was used to isolate nonpathogenic mutants of xanthomonas campestris pv. glycines 8ra, which causes bacterial pustule disease in soybean. a 6.1-kb dna region in which a mutation gave loss of pathogenicity was isolated and found to carry six open reading frames (orfs). four orfs had homology with hrcu, hrcv, hrcr, and hrcs genes of ralstonia solanacearum and x. campestris pv. vesicatoria. one nonpathogenic mutant, x. campestris pv. glycines h80, lost pathogenicity on soybean ... | 1999 | 10478481 |
| a transposon insertion in the gumg homologue of xanthomonas oryzae pv. oryzae causes loss of extracellular polysaccharide production and virulence. | xanthomonas oryzae pv. oryzae causes a serious disease of rice called bacterial leaf blight. it produces copious amounts of extracellular polysaccharide (eps). an eps- and virulence-deficient mutant of x. oryzae pv. oryzae was isolated by tn5 mutagenesis. the mutant allele in this strain was cloned by transposon tagging in the escherichia coli vector pbluescript and the dna sequences flanking the transposon insertion site were determined. computer-based similarity searches in the dna database us ... | 1999 | 10481086 |
| role of the alkyl hydroperoxide reductase (ahpcf) gene in oxidative stress defense of the obligate anaerobe bacteroides fragilis. | in this study we report the identification and role of the alkyl hydroperoxide reductase (ahp) gene in bacteroides fragilis. the two components of ahp, ahpc, and ahpf, are organized in an operon, and the deduced amino acid sequences revealed that b. fragilis ahpcf shares approximately 60% identity to orthologues in other gram-positive and gram-negative bacteria. northern blot hybridization analysis of total rna showed that the ahpcf genes were transcribed as a polycistronic 2.4-kb mrna and that ... | 1999 | 10482511 |
| identification of a pathogenicity island, which contains genes for virulence and avirulence, on a large native plasmid in the bean pathogen pseudomonas syringae pathovar phaseolicola. | the 154-kb plasmid was cured from race 7 strain 1449b of the phytopathogen pseudomonas syringae pv. phaseolicola (pph). cured strains lost virulence toward bean, causing the hypersensitive reaction in previously susceptible cultivars. restoration of virulence was achieved by complementation with cosmid clones spanning a 30-kb region of the plasmid that contained previously identified avirulence (avr) genes avrd, avrpphc, and avrpphf. single transposon insertions at multiple sites (including one ... | 1999 | 10485919 |