Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| 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 |
| structure-function analysis of xcpp, a component involved in general secretory pathway-dependent protein secretion in pseudomonas aeruginosa. | the general secretory pathway of pseudomonas aeruginosa is required for the transport of signal peptide-containing exoproteins across the cell envelope. after completion of the sec-dependent translocation of exoproteins across the inner membrane and cleavage of the signal peptide, the xcp machinery mediates translocation across the outer membrane. this machinery consists of 12 components, of which xcpq (gspd) is the sole outer membrane protein. xcpq forms a multimeric ring-shaped structure, with ... | 1999 | 10383969 |
| 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 |
| an outbreak of nonflocculating catabolic populations caused the breakdown of a phenol-digesting activated-sludge process. | activated sludge was fed phenol as the sole carbon source, and the phenol-loading rate was increased stepwise from 0.5 to 1.0 g liter-1 day-1 and then to 1.5 g liter-1 day-1. after the loading rate was increased to 1.5 g liter-1 day-1, nonflocculating bacteria outgrew the sludge, and the activated-sludge process broke down within 1 week. the bacterial population structure of the activated sludge was analyzed by temperature gradient gel electrophoresis (tgge) of pcr-amplified 16s ribosomal dna (r ... | 1999 | 10388669 |
| determination of total protein content of bacterial cells by sypro staining and flow cytometry. | an assay has been developed for measuring protein biomass of marine planktonic bacteria by flow cytometry. the method was calibrated by using five species of bacteria (an arcobacter sp., a cytophaga sp., an oceanospirillum sp., a pseudoalteromonas sp., and a vibrio sp.) recently isolated from seawater samples and grown in culture at different temperatures. the intensity of sypro-protein fluorescence of these bacteria strongly correlated with their total protein content, measured by the bicinchon ... | 1999 | 10388732 |
| 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 |
| identification of the promoter region of the xanthomonas campestris pv. citri reca gene responsible for induction by dna-damaging agents. | the abundance of the reca protein and of reca transcripts was markedly increased on exposure of xanthomonas campestris pathovar citri to various dna-damaging agents, including mitomycin c. the promoter sequence responsible for mediating the sensitivity of reca expression to dna damage was investigated by subcloning a 426-bp restriction fragment of the 5' untranslated and coding region of the gene into a promoterless vector containing the luxab genes of vibrio fischeri. xanthomonas campestris pv. ... | 1999 | 10418131 |
| 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 |
| differential induction of plant volatile biosynthesis in the lima bean by early and late intermediates of the octadecanoid-signaling pathway. | plants are able to respond to herbivore damage with de novo biosynthesis of an herbivore-characteristic blend of volatiles. the signal transduction initiating volatile biosynthesis may involve the activation of the octadecanoid pathway, as exemplified by the transient increase of endogenous jasmonic acid (ja) in leaves of lima bean (phaseolus lunatus) after treatment with the macromolecular elicitor cellulysin. within this pathway lima bean possesses at least two different biologically active si ... | 1999 | 10482670 |
| spider mite-induced (3s)-(e)-nerolidol synthase activity in cucumber and lima bean. the first dedicated step in acyclic c11-homoterpene biosynthesis. | many plant species respond to herbivory with de novo production of a mixture of volatiles that attracts carnivorous enemies of the herbivores. one of the major components in the blend of volatiles produced by many different plant species in response to herbivory by insects and spider mites is the homoterpene 4,8-dimethyl-1,3(e), 7-nonatriene. one study (j. donath, w. boland [1995] phytochemistry 39: 785-790) demonstrated that a number of plant species can convert the acyclic sesquiterpene alcoho ... | 1999 | 10482672 |
| 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 |
| a rolling-circle miniplasmid of xanthomonas campestris pv. glycines: the nucleotide sequence and its use as a cloning vector. | the indigenous multicopy miniplasmid (pxg33) of xanthomonas campestris pv. glycines was entirely sequenced and evaluated as a cloning vector for xanthomonas. the pxg33 contains 1738 bp and the nucleotide sequence revealed a consensus nicking site (tgata) described for the pc194 family of rolling-circle replicating (rcr) plasmids. this nicking site is embebbed in a region of high potential to form a number of stem-loop structures. the predicted protein (rep) showed conserved amino acid residues a ... | 1999 | 10489329 |
| genomic subtractive hybridization and selective capture of transcribed sequences identify a novel salmonella typhimurium fimbrial operon and putative transcriptional regulator that are absent from the salmonella typhi genome. | salmonella typhi, the etiologic agent of typhoid fever, is adapted to the human host and unable to infect nonprimate species. the genetic basis for host specificity in s. typhi is unknown. the avirulence of s. typhi in animal hosts may result from a lack of genes present in the broad-host-range pathogen salmonella typhimurium. genomic subtractive hybridization was successfully employed to isolate s. typhimurium genomic sequences which are absent from the s. typhi genome. these genomic subtracted ... | 1999 | 10496884 |
| functions of two types of nadh oxidases in energy metabolism and oxidative stress of streptococcus mutans. | we have previously identified two distinct nadh oxidases corresponding to h(2)o(2)-forming oxidase (nox-1) and h(2)o-forming oxidase (nox-2) induced in streptococcus mutans. sequence analyses indicated a strong similarity between nox-1 and ahpf, the flavoprotein component of salmonella typhimurium alkyl hydroperoxide reductase; an open reading frame upstream of nox-1 also showed homology to ahpc, the direct peroxide-reducing component of s. typhimurium alkyl hydroperoxide reductase. to determine ... | 1999 | 10498705 |
| the pila gene of xanthomonas campestris pv. citri is required for infection by the filamentous phage cf. | host factors that are important for infection of xanthomonas campestris pv. citri by the filamentous bacteriophage cf were investigated by transposon mutagenesis with tn5tac1. a mutant, xt501, that was resistant to cf infection was recovered, showing that the gene inactivated by the transposon is required for infection by the phage but not for cf replication or assembly. a 1.7-kb saci-apai dna fragment from xt501 containing the bacterial dna flanking one end of the transposon was cloned and show ... | 1999 | 10503532 |
| unraveling the function of glycosyltransferases in streptococcus thermophilus sfi6. | streptococcus thermophilus sfi6 produces a texturizing exopolysaccharide (eps) consisting of a -->3)[alpha-d-galp-(1-->6)]-beta-d-glcp-(1-->3)-alpha-d-galpnac-(1--> 3)-beta-d-galp-(1--> repeating unit. we previously identified and analyzed a 14.5-kb gene cluster from s. thermophilus sfi6 consisting of 13 genes responsible for its eps production. within this gene cluster, we found a central region of genes (epse, epsf, epsg, and epsi) that showed similarity to glycosyltransferases. in this study, ... | 1999 | 10515925 |
| identification of new early markers of the hypersensitive response in arabidopsis thaliana(1). | new molecular markers of the hypersensitive response (hr) of arabidopsis thaliana to the bacterial pathogen xanthomonas campestris pv. campestris (x.c.c.) have been identified by differential screening of a cdna library constructed from suspension cells inoculated by an hr-inducing strain in the presence of cycloheximide. seven families of genes (called athsr) have been isolated, show similarities to voltage-dependent anion channels (vdac) and alternative oxidases, or are novel proteins. athsr g ... | 1999 | 10518009 |
| the o-chain polysaccharide of the lipopolysaccharide of xanthomonas campestris pv. begoniae gspb 525 is a partially l-xylosylated l-rhamnan. | the o-chain polysaccharide (ops) of the lipopolysaccharide of xanthomonas campestris pv. begoniae gspb 525 was found to contain l-rhamnose and l-xylose in the ratio 1:0.6. the ops lacked strict regularity because of nonstoichiometric xylosylation of the main rhamnan chain. based on methylation analysis, smith degradation, and 1h and 13c nmr spectroscopy, including cosy, tocsy, noesy, and h-detected 1h,13c heteronuclear multiple-quantum coherence (hmqc) experiments, the following structure of the ... | 1999 | 10520263 |
| induction of the viable but non-culturable condition in xanthomonas campestris pv. campestris in liquid microcosms and sterile soil. | xanthomonas campestris pathovar campestris was examined for the ability to enter the viable but non-culturable (vbnc) state. when nutrients were removed from a bacterial culture, the culturability dropped to undetectable levels within 6 weeks while the concentration of viable cells remained above 10(5) cells ml(-1). addition of cupric sulfate facilitated this process. when bacteria were placed in autoclaved soil, culturability dropped by at least four logs within 5 days of the experiment while t ... | 1999 | 10525176 |
| molecular characterization of the locus encoding biosynthesis of the lipopolysaccharide o antigen of escherichia coli serotype o113. | shiga toxigenic escherichia coli (stec) strains are a diverse group of organisms capable of causing severe gastrointestinal disease in humans. within the stec family, eae-positive stec strains, particularly those belonging to serogroups o157 and o111, appear to have greater virulence for humans. however, in spite of being eae negative, stec strains belonging to serogroup o113 have frequently been associated with cases of severe stec disease, including hemolytic-uremic syndrome (hus). western blo ... | 1999 | 10531250 |
| identification of regions of the chromosome of neisseria meningitidis and neisseria gonorrhoeae which are specific to the pathogenic neisseria species. | neisseria meningitidis and neisseria gonorrhoeae give rise to dramatically different diseases. their interactions with the host, however, do share common characteristics: they are both human pathogens which do not survive in the environment and which colonize and invade mucosa at their port of entry. it is therefore likely that they have common properties that might not be found in nonpathogenic bacteria belonging to the same genetically related group, such as neisseria lactamica. their common p ... | 1999 | 10531275 |
| mutations in the regulatory gene hrpg of xanthomonas campestris pv. vesicatoria result in constitutive expression of all hrp genes. | hrpg is a key regulatory gene for transcriptional activation of pathogenicity genes (hrp) of xanthomonas campestris pv. vesicatoria. we identified three mutations in hrpg which render hrp gene expression constitutive in normally suppressing medium. the mutations in hrpg result in novel amino acid substitutions compared to mutations in related proteins, such as ompr. in addition, mutated hrpg enhances the timing and intensity of plant reactions in infection assays. | 1999 | 10542187 |
| isolation of polymyxin b-susceptible mutants of burkholderia pseudomallei and molecular characterization of genetic loci involved in polymyxin b resistance. | burkholderia pseudomallei is a gram-negative bacterium that causes the disease known as melioidosis. this pathogen is endemic to southeast asia and northern australia and is particularly problematic in northeastern thailand. it has been previously reported that b. pseudomallei is resistant to the killing action of cationic antimicrobial peptides, including human neutrophil peptide, protamine sulfate, poly-l-lysine, magainins, and polymyxins. recently, we have also found that the virulent clinica ... | 1999 | 10543742 |
| distribution of tetracycline resistance genes and transposons among phylloplane bacteria in michigan apple orchards. | the extent and nature of tetracycline resistance in bacterial populations of two apple orchards with no or a limited history of oxytetracycline usage were assessed. tetracycline-resistant (tc(r)) bacteria were mostly gram negative and represented from 0 to 47% of the total bacterial population on blossoms and leaves (versus 26 to 84% for streptomycin-resistant bacteria). a total of 87 isolates were screened for the presence of specific tc(r) determinants. tc(r) was determined to be due to the pr ... | 1999 | 10543801 |
| a physical map of the chromosome of xanthomonas campestris pv. phaseoli var. fuscans bxpf65. | a physical map of the xanthomonas campestris pv. phaseoli var. fuscans bxpf65 chromosome was constructed by pfge and southern hybridization. the chromosome was 3938 kb and was composed of 39 xbai restriction fragments. the size is close to that estimated for x. campestris pv. campestris based on dna renaturation kinetics. macrorestriction fragments containing genes for a 16s rrna, pectate lyase, two-component regulatory system and hrp cluster were located on the physical map. each of these probe ... | 1999 | 10547448 |
| characterization of a ferric uptake regulator (fur) gene from xanthomonas campestris pv. phaseoli with unusual primary structure, genome organization, and expression patterns. | a 1.5kb dna fragment from xanthomonas campestris pv. phaseoli containing fur was characterized. fur is a single copy gene that is transcribed as a monocistronic mrna. the predicted amino acid sequence of xp fur showed extensive identity to other fur proteins. however, xp fur has many distinct features, particularly a lack of cysteine residues in the conserved metal-binding motifs and unusual modifications in the carboxy-terminus region. the nucleotide sequences of fur genes from four other xanth ... | 1999 | 10548726 |
| purification and characterization of s-adenosyl-l-methionine: desoxyhemigossypol-6-o-methyltransferase from cotton plants. an enzyme capable of methylating the defense terpenoids of cotton. | cotton contains a unique group of terpenoids including desoxyhemigossypol, hemigossypol, gossypol, hemigossypolone, and the heliocides that are part of the plant's defense system against pathogenic fungi and insects. desoxyhemigossypol is a key intermediate in the biosynthesis of these compounds. we have isolated, purified, and characterized from cotton stele tissue infected with verticillium dahliae a methyltransferase (s-adenosyl-l-met: desoxyhemigossypol-6-o-methyltransferase) that specifical ... | 1999 | 10557251 |
| immunochemical characterization and taxonomic evaluation of the o polysaccharides of the lipopolysaccharides of pseudomonas syringae serogroup o1 strains. | the o polysaccharide (ops) of the lipopolysaccharide (lps) of pseudomonas syringae pv. atrofaciens imv 7836 and some other strains that are classified in serogroup o1 was shown to be a novel linear alpha-d-rhamnan with the tetrasaccharide o repeat -->3)-alpha-d-rhap-(1-->3)-alpha-d-rhap-(1-->2)-alpha-d-r hap-(1-->2)- alpha-d-rhap-(1--> (chemotype 1a). the same alpha-d-rhamnan serves as the backbone in branched opss with lateral (alpha1-->3)-linked d-rhap, (beta1-->4)-linked d-glcpnac, and (alpha ... | 1999 | 10559159 |
| use of 16s rdna sequences as signature characters to identify xylella fastidiosa. | the nucleotide sequences of 16s rdnas (coding for the small subunit ribosomal rnas) were used to identify xylella fastidiosa, a nutritionally fastidious plant pathogenic bacterium. the near-complete 16s rdnas from nine strains of xyl. fastidiosa, including seven pathotypes and one strain of xanthomonas campestris pv. campestris, were amplified through pcr with two conserved primers (forward primer 5'-aga gtt tga tcc tgg ctc ag-3' and reverse primer 5'-aag gag gtg atc cag cc-3') and sequenced. th ... | 2000 | 10568800 |
| global gaca-steered control of cyanide and exoprotease production in pseudomonas fluorescens involves specific ribosome binding sites. | the conserved two-component regulatory system gacs/gaca determines the expression of extracellular products and virulence factors in a variety of gram-negative bacteria. in the biocontrol strain cha0 of pseudomonas fluorescens, the response regulator gaca is essential for the synthesis of extracellular protease (apra) and secondary metabolites including hydrogen cyanide. gaca was found to exert its control on the hydrogen cyanide biosynthetic genes (hcnabc) and on the apra gene indirectly via a ... | 1999 | 10570200 |
| expression of the bs2 pepper gene confers resistance to bacterial spot disease in tomato. | the bs2 resistance gene of pepper specifically recognizes and confers resistance to strains of xanthomonas campestris pv. vesicatoria that contain the corresponding bacterial avirulence gene, avrbs2. the involvement of avrbs2 in pathogen fitness and its prevalence in many x. campestris pathovars suggests that the bs2 gene may be durable in the field and provide resistance when introduced into other plant species. employing a positional cloning strategy, the bs2 locus was isolated and the gene wa ... | 1999 | 10570214 |
| a novel myb oncogene homologue in arabidopsis thaliana related to hypersensitive cell death. | a novel myb oncogene homologue (atmyb30) has been isolated by differential screening of a cdna library prepared from xanthomonas campestris pv. campestris (x. campestris)-inoculated arabidopsis thaliana cells cultured in the presence of cycloheximide. atmyb30 is a single-copy gene, and the encoded protein contains a myb domain highly homologous to other plant and animal myb proteins. analyses of transcript levels in a. thaliana plants, or in cultured a. thaliana cells infected with either virule ... | 1999 | 10571865 |
| genetic dissection of the outer membrane secretin puld: are there distinct domains for multimerization and secretion specificity? | linker and deletion mutagenesis and gene fusions were used to probe the possible domain structure of the dodecameric outer membrane secretin puld from the pullulanase secretion pathway of klebsiella oxytoca. insertions of 24 amino acids close to or within strongly predicted and highly conserved amphipathic beta strands in the c-terminal half of the polypeptide (the beta domain) abolished sodium dodecyl sulfate (sds)-resistant multimer formation that is characteristic of this protein, whereas ins ... | 1999 | 10572123 |
| cloning, sequencing, and characterization of genomic subtracted sequences from listeria monocytogenes. | individual sequences of a genomic subtracted, pcr-amplified, mixed-sequence probe (gs probe) were cloned and sequenced. the gs probe differentiated restriction fragment length polymorphism patterns for listeria monocytogenes but did not hybridize with members of other bacterial genera. sequence analysis identified several l. monocytogenes sequences already present in the genbank database; the putative identities of other sequences were inferred from homology data, and still other sequences did n ... | 1999 | 10583999 |
| requirement for phosphoglucose isomerase of xanthomonas campestris in pathogenesis of citrus canker. | a mutant (xt906) of xanthomonas campestris pv. citri, the causal agent of citrus canker, was induced by insertion of the transposon tn5tac1 and isolated. this mutant did not grow or elicit canker disease in citrus leaves but was still able to induce a hypersensitive response in a nonhost plant (the common bean). the mutant was also unable to grow on minimal medium containing fructose or glycerol as the sole carbon source. a 2.5-kb fragment of wild-type dna that complemented the mutant phenotype ... | 1999 | 10584018 |
| construction and characterization of regulated l-arabinose-inducible broad host range expression vectors in xanthomonas. | several versions of broad host range (bhr), l-arabinose-inducible expression vectors were constructed. these expression vectors were based on a high copy number bhr pbbr1mcs-4 replicon that could replicate in both enteric and non-enteric gram-negative bacteria. two versions of expression cassettes containing multiple cloning sites either with or without a ribosome binding site were placed under transcriptional control of the escherichia coli bad promoter and arac gene. three versions of vectors ... | 1999 | 10585541 |
| requirement of functional ethylene-insensitive 2 gene for efficient resistance of arabidopsis to infection by botrytis cinerea. | inoculation of wild-type arabidopsis plants with the fungus alternaria brassicicola results in systemic induction of genes encoding a plant defensin (pdf1.2), a basic chitinase (pr-3), and an acidic hevein-like protein (pr-4). pathogen-induced induction of these three genes is almost completely abolished in the ethylene-insensitive arabidopsis mutant ein2-1. this indicates that a functional ethylene signal transduction component (ein2) is required in this response. the ein2-1 mutants were found ... | 1999 | 10594097 |
| a gene involved in quinate metabolism is specific to one dna homology group of xanthomonas campestris. | a gene involved in quinate metabolism was cloned from xanthomonas campestris pv. juglandis strain c5. the gene, quma, located on a 4. 2-kb kpni-ecorv fragment in plasmid pqm38, conferred quinate metabolic activity to x. c. pv. celebensis. tn3-spice insertional analyses further located the quma gene on a region of about 3.0 kb within pqm38. nucleotide sequencing of this 3.0-kb fragment reveals that the coding region of quma is 2373 bp, the deduced amino acid sequence of which closely resembles a ... | 1999 | 10594704 |
| an approach to obtain specific polyclonal antisera to xanthomonas campestris pv. cyamopsidis and its potential application in indexing of infected seeds of guar. | clusterbean seed health testing is warranted since the pathogen (xanthomonas campestris pv. cyamopsidis (xccy)) is seed-borne and seed-transmitted. a polyclonal antibody was developed in rabbit via subcutaneous and intramuscular injections and characterized for sensitivity, specificity and its applicability to elisa which: (i) was sensitive in detecting as few as 102 cells ml - 1 at a titre of 1: 4000; (ii) was specific, since it reacted only with xccy and not with other xanthomonads; (iii) reac ... | 1999 | 10594712 |
| differential and independent roles of a sigma(32) homolog (rpoh) and an hrca repressor in the heat shock response of agrobacterium tumefaciens. | the heat shock response in alpha proteobacteria is unique in that a combination of two regulators is involved: a positive regulator, rpoh (sigma(32) homolog), found in the alpha, beta, and gamma proteobacteria, and a negative regulator, hrca, widely distributed in eubacteria but not in the gamma proteobacteria. to assess the differential roles of the two regulators in these bacteria, we cloned the hrca-grpe operon of agrobacterium tumefaciens, analyzed its transcription, and constructed deletion ... | 1999 | 10601208 |
| hbar, a 4-hydroxybenzoate sensor and fnr-crp superfamily member, regulates anaerobic 4-hydroxybenzoate degradation by rhodopseudomonas palustris. | under anaerobic conditions, structurally diverse aromatic compounds are catabolized by bacteria to form benzoyl-coenzyme a (benzoyl-coa), the starting compound for a central reductive pathway for aromatic ring degradation. the structural genes required for the conversion of 4-hydroxybenzoate (4-hba) to benzoyl-coa by rhodopseudomonas palustris have been identified. here we describe a regulatory gene, hbar, that is part of the 4-hba degradation gene cluster. an hbar mutant that was constructed wa ... | 2000 | 10613868 |
| role of leaf surface sugars in colonization of plants by bacterial epiphytes. | the relationship between nutrients leached onto the leaf surface and the colonization of plants by bacteria was studied by measuring both the abundance of simple sugars and the growth of pseudomonas fluorescens on individual bean leaves. data obtained in this study indicate that the population size of epiphytic bacteria on plants under environmentally favorable conditions is limited by the abundance of carbon sources on the leaf surface. sugars were depleted during the course of bacterial coloni ... | 2000 | 10618250 |
| mechanism of oxygen availability from hydrogen peroxide to aerobic cultures of xanthomonas campestris. | fundamental studies on the availability of oxygen from the decomposition of h(2)o(2), in vivo, by xanthomonas campestris, when h(2)o(2) is used as an oxygen source are presented. it was found that the h(2)o(2) added extracellularly (0.1-6 mm) was decomposed intracellularly. further, when h(2)o(2) was added, the flux of h(2)o(2) into the cell, is regulated by the cell. the steady-state h(2)o(2) flux into the cell was estimated to be 9.7 x 10(-8) mol m(-2) s(-1). in addition, it was proved that th ... | 2000 | 10620764 |
| bacterial primary colonization and early succession on surfaces in marine waters as determined by amplified rrna gene restriction analysis and sequence analysis of 16s rrna genes. | the nearly universal colonization of surfaces in marine waters by bacteria and the formation of biofilms and biofouling communities have important implications for ecological function and industrial processes. however, the dynamics of surface attachment and colonization in situ, particularly during the early stages of biofilm establishment, are not well understood. experimental surfaces that differed in their degrees of hydrophilicity or hydrophobicity were incubated in a salt marsh estuary tida ... | 2000 | 10653705 |
| isolation, partial sequencing, and expression of pathogenesis-related cdna genes from pepper leaves infected by xanthomonas campestris pv. vesicatoria. | specific cdnas showing differential expression in bacteria-infected pepper leaves as opposed to healthy leaves were isolated from a pepper cdna library from hypersensitive response (hr) lesions of leaves infected with an avirulent strain of xanthomonas campestris pv. vesicatoria. among a total of 282 cdna clones tested, 36 individual cdna genes (13%) hybridized strongly or differentially to the cdna probes from bacteria-infected leaves. ten capsicum annuum-induced (cai) genes encoding putative t ... | 2000 | 10656596 |
| cdna-aflp analysis of differential gene expression in the prokaryotic plant pathogen erwinia carotovora. | for studies of differential gene expression in prokaryotes, methods for synthesizing representative cdna populations are required. here, a technique is described for the synthesis of cdna from the potato pathogens erwinia carotovora subsp. atroseptica (eca) and erwinia carotovora subsp. carotovora (ecc) using a combination of short oligonucleotide (11-mer) primers that were known to anneal to conserved sequences in the 3' regions of enterobacterial genes. specific pcr amplifications with primers ... | 2000 | 10658663 |
| effects of calcium and calcium chelators on growth and morphology of escherichia coli l-form nc-7. | growth of a wall-less, l-form of escherichia coli specifically requires calcium, and in its absence, cells ceased dividing, became spherical, swelled, developed large vacuoles, and eventually lysed. the key cell division protein, ftsz, was present in the l-form at a concentration five times less than that in the parental strain. one interpretation of these results is that the l-form possesses an enzoskeleton partly regulated by calcium. | 2000 | 10671467 |
| expression analysis and characterization of the mutant of a growth-phase- and starvation-regulated monofunctional catalase gene from xanthomonas campestris pv. phaseoli. | analysis of the xanthomonas campestris pv. phaseoli (xp) catalase profile using an activity gel revealed at least two distinct monofunctional catalase isozymes denoted kat1 and kat2. kat1 was expressed throughout growth, whereas kat2 was expressed only during the stationary phase of growth. the nucleotide sequence of a previously isolated monofunctional catalase gene, xp kate, was determined. the deduced amino acid sequence of xp kate showed a high percentage identity to an atypical group of mon ... | 2000 | 10675038 |
| nitric oxide modulates the activity of tobacco aconitase. | recent evidence suggests an important role for nitric oxide (no) signaling in plant-pathogen interactions. additional elucidation of the role of no in plants will require identification of no targets. since aconitases are major no targets in animals, we examined the effect of no on tobacco (nicotiana tabacum) aconitase. the tobacco aconitases, like their animal counterparts, were inhibited by no donors. the cytosolic aconitase in animals, in addition to being a key redox and no sensor, is conver ... | 2000 | 10677450 |
| actinobacillus pleuropneumoniae iron transport: a set of exbbd genes is transcriptionally linked to the tbpb gene and required for utilization of transferrin-bound iron. | upon iron restriction, actinobacillus pleuropneumoniae has been shown to express the transferrin-binding proteins tbpb and tbpa, both of which have been implied to be important virulence factors. in order to identify additional iron-regulated proteins, we cloned and analyzed the region upstream of the transferrin-binding protein genes in an a. pleuropneumoniae serotype 7 strain. we located immediately upstream of the tbpb gene two open reading frames which were 43% homologous to the neisserial e ... | 2000 | 10678921 |
| identification of a lexa gene in, and construction of a lexa mutant of, xanthomonas campestris pv. citri. | the lexa gene of xanthomonas campestris pathovar citri (x.c. pv. citri) was cloned and sequenced. the 639-bp open reading frame encodes a protein of 213 amino acids that shares substantial sequence homology with the products of previously characterized lexa genes, sharing 46% identity with the lexa protein of escherichia coli. amino acids required for autocatalytic cleavage of lexa are conserved in the x.c. pv. citri protein, whereas domains thought to mediate dna binding differ markedly from th ... | 2000 | 10688691 |
| association of the cytoplasmic membrane protein xpsn with the outer membrane protein xpsd in the type ii protein secretion apparatus of xanthomonas campestris pv. campestris. | an xps gene cluster composed of 11 open reading frames is required for the type ii protein secretion in xanthomonas campestris pv. campestris. immediately upstream of the xpsd gene, which encodes an outer membrane protein that serves as the secretion channel by forming multimers, there exists an open reading frame (previously designated orf2) that could encode a protein of 261 amino acid residues. its n-terminal hydrophobic region is a likely membrane-anchoring sequence. antibody raised against ... | 2000 | 10692359 |
| succession of microbial communities during hot composting as detected by pcr-single-strand-conformation polymorphism-based genetic profiles of small-subunit rrna genes. | a cultivation-independent technique for genetic profiling of pcr-amplified small-subunit rrna genes (ssu rdna) was chosen to characterize the diversity and succession of microbial communities during composting of an organic agricultural substrate. pcr amplifications were performed with dna directly extracted from compost samples and with primers targeting either (i) the v4-v5 region of eubacterial 16s rrna genes, (ii) the v3 region in the 16s rrna genes of actinomycetes, or (iii) the v8-v9 regio ... | 2000 | 10698754 |
| survival and epiphytic fitness of a nonpathogenic mutant of xanthomonas campestris pv. glycines. | xanthomonas campestris pv. glycines is the causal agent of bacterial pustule disease of soybeans. the objective of this work was to construct a nonpathogenic mutant derived from the pathogenic wild-type strain yr32 and to evaluate its effectiveness in preventing growth of its parent on the soybean phyllosphere. a mini-tn5-derived transposon was used to generate nonpathogenic mutants. southern hybridization and pulsed-field gel electrophoresis confirmed the presence of a single transposon in each ... | 2000 | 10698789 |
| microbial relatives of the seed storage proteins of higher plants: conservation of structure and diversification of function during evolution of the cupin superfamily. | this review summarizes the recent discovery of the cupin superfamily (from the latin term "cupa," a small barrel) of functionally diverse proteins that initially were limited to several higher plant proteins such as seed storage proteins, germin (an oxalate oxidase), germin-like proteins, and auxin-binding protein. knowledge of the three-dimensional structure of two vicilins, seed proteins with a characteristic beta-barrel core, led to the identification of a small number of conserved residues a ... | 2000 | 10704478 |
| [examining interaction of phages with microorganisms by fluorometry and electro-orientation spectroscopy]. | bacterial sensitivity to different various phages was examined by electro-orientation spectroscopy, fluorometry, and electron microscopy. the strains of pseudomonas aeruginosa, staphylococcus aureus, yersinia pestis, mycobacterium smegmatis, and xanthomonas campestris were used. the fluorescence intensity of a membranotropic agent in the ans-cell-phage system was shown to depend on the interaction of a bacterial virus and a microorganism. fluorometric data correlated with electro-orientation spe ... | 1999 | 10709463 |
| salicylic acid mediated by the oxidative burst is a key molecule in local and systemic responses of cotton challenged by an avirulent race of xanthomonas campestris pv malvacearum. | we analyzed the production of reactive oxygen species, the accumulation of salicylic acid (sa), and peroxidase activity during the incompatible interaction between cotyledons of the cotton (gossypium hirsutum) cv reba b50/xanthomonas campestris pv malvacearum (xcm) race 18. sa was detected in petioles of cotyledons 6 h after infection and 24 h post inoculation in cotyledons and untreated leaves. the first peak of sa occurred 3 h after generation of superoxide (o(2)(.-)), and was inhibited by inf ... | 2000 | 10712539 |
| identification of two novel hrp-associated genes in the hrp gene cluster of xanthomonas oryzae pv. oryzae. | we have cloned a hrp gene cluster from xanthomonas oryzae pv. oryzae. bacteria with mutations in the hrp region have reduced growth in rice leaves and lose the ability to elicit a hypersensitive response (hr) on the appropriate resistant cultivars of rice and the nonhost plant tomato. a 12,165-bp portion of nucleotide sequence from the presumed left end and extending through the hrpb operon was determined. the region was most similar to hrp genes from xanthomonas campestris pv. vesicatoria and r ... | 2000 | 10714988 |
| secreted enzymatic activities of wild-type and pild-deficient legionella pneumophila. | legionella pneumophila, the agent of legionnaires' disease, is an intracellular pathogen of protozoa and macrophages. previously, we had determined that the legionella pild gene is involved in type iv pilus biogenesis, type ii protein secretion, intracellular infection, and virulence. since the loss of pili and a protease do not account for the infection defect exhibited by a pild-deficient strain, we sought to define other secreted proteins absent in the mutant. based upon the release of p-nitr ... | 2000 | 10722574 |
| bordetella pertussis tonb, a bvg-independent virulence determinant. | in gram-negative bacteria, high-affinity iron uptake requires the tonb/exbb/exbd envelope complex to release iron chelates from their specific outer membrane receptors into the periplasm. based on sequence similarities, the bordetella pertussis tonb exbb exbd locus was identified on a cloned dna fragment. the tight organization of the three genes suggests that they are cotranscribed. a putative fur-binding sequence located upstream from tonb was detected in a fur titration assay, indicating that ... | 2000 | 10722583 |
| type iv pilus genes pila and pilc of pseudomonas stutzeri are required for natural genetic transformation, and pila can be replaced by corresponding genes from nontransformable species. | pseudomonas stutzeri lives in terrestrial and aquatic habitats and is capable of natural genetic transformation. after transposon mutagenesis, transformation-deficient mutants were isolated from a p. stutzeri jm300 strain. in one of them a gene which coded for a protein with 75% amino acid sequence identity to pilc of pseudomonas aeruginosa, an accessory protein for type iv pilus biogenesis, was inactivated. the presence of type iv pili was demonstrated by susceptibility to the type iv pilus-dep ... | 2000 | 10735861 |
| functional analysis of gapped microbial genomes: amino acid metabolism of thiobacillus ferrooxidans. | a gapped genome sequence of the biomining bacterium thiobacillus ferrooxidans strain atcc23270 was assembled from sheared dna fragments (3.2-times coverage) into 1,912 contigs. a total of 2,712 potential genes (orfs) were identified in 2.6 mbp (megabase pairs) of thiobacillus genomic sequence. of these genes, 2,159 could be assigned functions by using the wit-pro/emp genome analysis system, most with a high degree of certainty. nine hundred of the genes have been assigned roles in metabolic path ... | 2000 | 10737802 |
| superoxide dismutase activity in pseudomonas putida affects utilization of sugars and growth on root surfaces. | to investigate the role of superoxide dismutases (sod) in root colonization and oxidative stress, mutants of pseudomonas putida lacking manganese-superoxide dismutase (mnsod) (soda), iron-superoxide dismutase (fesod) (sodb), or both were generated. the soda sodb mutant did not grow on components washed from bean root surfaces or glucose in minimal medium. the sodb and soda sodb mutants were more sensitive than wild type to oxidative stress generated within the cell by paraquat treatment. in sing ... | 2000 | 10742227 |
| mutants of xanthomonas oryzae pv. oryzae deficient in general secretory pathway are virulence deficient and unable to secrete xylanase. | xanthomonas oryzae pv. oryzae (xoo) causes bacterial leaf blight, a serious disease of rice. a virulence- and xylanase-deficient mutant of xoo was isolated following ethyl methane sulfonate (ems) mutagenesis. a cosmid clone that restored virulence and xylanase secretion was obtained from a genomic library by functional complementation. transposon mutagenesis and marker exchange studies revealed genes on the cloned dna that were required for xylanase production and virulence. sequence analysis wi ... | 2000 | 10755302 |
| genotypic characterization of xanthomonad strains isolated from passion fruit plants (passiflora spp.) and their relatedness to different xanthomonas species. | the genetic diversity of 55 xanthomonad strains isolated from passion fruit plants (passiflora spp.) and identified as xanthomonas campestris pv. passiflorae was initially assessed by randomly amplified polymorphic dna (rapd) analysis. the strains showed a high level of polymorphism with almost unique fingerprints. fifteen clusters with a similarity of approximately 70% were identified, three of which were prevalent. there was a correlation between the clusters and the geographic origin of the s ... | 2000 | 10758892 |
| [rapd-markers linked to the locus for resistance to the race 4 pathogen for black rot, xanthomonas campestris pv. campestris (pamm.) dow., in brassica rapa l]. | association between the rapd markers and the resistance to race 4 of the black rot causative agent was studied in brassica rapa l. experiments were carried out using doubled haploid lines, obtained via crosses between the race 4-susceptible fodder turnip and resistant pak-choi, and the f2 progeny of the crosses between the doubled haploid lines with contrasting resistance. the we(22)980 rapd marker inherited from the pak-choi and associated with the clubroot susceptibility was also linked to the ... | 2000 | 10779910 |
| the pseudomonas syringae hrp pathogenicity island has a tripartite mosaic structure composed of a cluster of type iii secretion genes bounded by exchangeable effector and conserved effector loci that contribute to parasitic fitness and pathogenicity in plants. | the plant pathogenic bacterium pseudomonas syringae is divided into pathovars differing in host specificity, with p. syringae pv. syringae (psy) and p. syringae pv. tomato (pto) representing particularly divergent pathovars. p. syringae hrp/hrc genes encode a type iii protein secretion system that appears to translocate avr and hop effector proteins into plant cells. dna sequence analysis of the hrp/hrc regions in psy 61, psy b728a, and pto dc3000 has revealed a hrp pathogenicity island (pai) wi ... | 2000 | 10781092 |
| prephenate dehydratase from the aphid endosymbiont (buchnera) displays changes in the regulatory domain that suggest its desensitization to inhibition by phenylalanine. | buchnera aphidicola, the prokaryotic endosymbiont of aphids, complements dietary deficiencies with the synthesis and provision of several essential amino acids. we have cloned and sequenced a region of the genome of b. aphidicola isolated from acyrthosiphon pisum which includes the two-domain aroq/phea gene. this gene encodes the bifunctional chorismate mutase-prephenate dehydratase protein, which plays a central role in l-phenylalanine biosynthesis. two changes involved in the overproduction of ... | 2000 | 10781569 |
| structure of the o-chain polysaccharide of the lipopolysaccharide of xanthomonas campestris pv. manihotis gspb 2755 and gspb 2364. | the o-chain polysaccharide of the lipopolysaccharide of xanthomonas campestris pv. manihotis strains gspb 2755 and gspb 2364 was studied by sugar and methylation analyses and 1h and 13c nmr spectroscopy, including 2d cosy, tocsy, noesy, and h-detected 1h, 13c heteronuclear multiple-quantum coherence (hmqc) experiments. the polysaccharide was found to contain l-rhamnose and l-xylose in the ratio 3:1, and the following structure of the tetrasaccharide repeating unit was established: [formula: see ... | 2000 | 10782308 |
| novel genes involved in the regulation of pathogenicity factor production within the rpf gene cluster of xanthomonas campestris. | the synthesis of extracellular enzymes and extracellular polysaccharide (eps) in xanthomonas campestris pathovar campestris (xcc) is subject to co-ordinate regulation by a cluster of genes called rpf (for regulation of pathogenicity factors). these genes are located within a 21.9 kb region of the chromosome isolated as the cosmid clone pij3020. the genes in the left-hand section of this region of the chromosome have previously been characterized. this paper reports on the genes in the right-hand ... | 2000 | 10784047 |
| design and evaluation of a lactobacillus manihotivorans species-specific rrna-targeted hybridization probe and its application to the study of sour cassava fermentation. | based on 16s rrna sequence comparison, we have designed a 20-mer oligonucleotide that targets a region specific to the species lactobacillus manihotivorans recently isolated from sour cassava fermentation. the probe recognized the rrna obtained from all the l. manihotivorans strains tested but did not recognize 56 strains of microorganisms from culture collections or directly isolated from sour cassava, including 29 species of lactic acid bacteria. this probe was then successfully used in quanti ... | 2000 | 10788405 |
| identification of the pgmg gene, encoding a bifunctional protein with phosphoglucomutase and phosphomannomutase activities, in the gellan gum-producing strain sphingomonas paucimobilis atcc 31461. | the pgmg gene of sphingomonas paucimobilis atcc 31461, the industrial gellan gum-producing strain, was cloned and sequenced. it encodes a 50,059-da polypeptide that has phosphoglucomutase (pgm) and phosphomannomutase (pmm) activities and is 37 to 59% identical to other bifunctional proteins with pgm and pmm activities from gram-negative species, including pseudomonas aeruginosa algc. purified pgmg protein showed a marked preference for glucose-1-phosphate (g1p); the catalytic efficiency was abou ... | 2000 | 10788412 |
| the tomato ethylene receptors nr and leetr4 are negative regulators of ethylene response and exhibit functional compensation within a multigene family. | the plant hormone ethylene is involved in many developmental processes, including fruit ripening, abscission, senescence, and leaf epinasty. tomato contains a family of ethylene receptors, designated leetr1, leetr2, nr, leetr4, and leetr5, with homology to the arabidopsis etr1 ethylene receptor. transgenic plants with reduced leetr4 gene expression display multiple symptoms of extreme ethylene sensitivity, including severe epinasty, enhanced flower senescence, and accelerated fruit ripening. the ... | 2000 | 10792050 |
| genetic polymorphism in xanthomonas albilineans strains originating from 11 geographical locations, revealed by two dna probes. | two dna fragments from xanthomonas albilineans were used as probes to study the molecular diversity among strains of this pathogen. two serologically distinct groups, serovars i and ii, could be differentiated by hybridization to the probes. these probes, designated 830 and 838, were cloned after subtractive dna hybridization of common sequences of xanthomonas campestris pv. vasculorum from a serovar i strain of x. albilineans. they did not hybridize to the dna of several other xanthomonads or t ... | 2000 | 10792648 |
| structure elucidation of the o-chain from the major lipopolysaccharide of the xanthomonas campestris strain 642. | a novel o-polysaccharide consisting of d-xylp and l-rhap in the molar ratio of 1:2.5 was identified as the major component in the lipopolysaccharide fraction of xanthomonas campestris strain 642, which is responsible for a new bacterial disease of the strawberry plant. its structure was mainly determined using chemical analysis, smith degradation and 1d and 2d nmr spectroscopy experiments as: carbohydrate sequence [see text]. | 2000 | 10795814 |
| response to xanthomonas campestris pv. vesicatoria in tomato involves regulation of ethylene receptor gene expression. | although ethylene regulates a wide range of defense-related genes, its role in plant defense varies greatly among different plant-microbe interactions. we compared ethylene's role in plant response to virulent and avirulent strains of xanthomonas campestris pv. vesicatoria in tomato (lycopersicon esculentum mill.). the ethylene-insensitive never ripe (nr) mutant displays increased tolerance to the virulent strain, while maintaining resistance to the avirulent strain. expression of the ethylene r ... | 2000 | 10806227 |