Publications

inhibition of hydrolytic enzyme activities and plant pathogen growth by invertase inhibitors.	the invertase inhibitory protein isolated from cyphomandra betacea sendt and solanum tuberosum inhibited the invertase activity from different species, genera and even plant family. furthermore, proteinaceous inhibitors are not invertase specific; fungal, bacterial and higher plant enzymes including polygalacturonase, pectinase, pectin lyase, alpha-l-arabinofuranosidase and beta-glucosidase are also shown to be inhibited. both inhibitors exhibited an in vitro antibacterial action against phytopa ...	2002	12365459
lipid peroxidation in cotton: xanthomonas interactions and the role of lipoxygenases during the hypersensitive reaction.	lipid peroxidation, often associated with hypersensitive cell death, may be initiated either by active oxygen species (aos) or lipoxygenases (lox). here we report a detailed analysis of this oxidative process in both incompatible and compatible interactions between the cotton cultivar reba b50 and xanthomonas campestris pv. malvacearum (xcm). the hypersensitive reaction (hr) was characterized by a massive production of polyunsaturated fatty acid (pufa) hydroperoxides together with typical tissue ...	2002	12366796
type iii-dependent translocation of the xanthomonas avrbs3 protein into the plant cell.	many plant pathogenic bacteria utilize a conserved type iii secretion system (ttss) to deliver effector proteins into the host tissue. indirect evidence has suggested that at least some effector proteins are translocated from the bacterial cytoplasm into the plant cell. using an immunocytochemical approach, we demonstrate that the type iii effector avrbs3 from xanthomonas campestris pv. vesicatoria localizes to nuclei of infected pepper leaves. importantly, avrbs3 translocation was observed in s ...	2002	12366827
getting across--bacterial type iii effector proteins on their way to the plant cell.	pathogenicity of most gram-negative bacterial plant pathogens depends on hrp (hypersensitive response and pathogenicity) genes, which control the ability to cause disease and to elicit specific defense responses in resistant plants. hrp genes encode a specialized type iii secretion (tts) system that mediates the vectorial delivery of bacterial effector proteins across both bacterial membranes as well as across the eukaryotic plasma membrane into the host cell cytosol. one well-studied effector p ...	2002	12374732
structures of the tricorn-interacting aminopeptidase f1 with different ligands explain its catalytic mechanism.	f1 is a 33.5 kda serine peptidase of the alpha/beta-hydrolase family from the archaeon thermoplasma acidophilum. subsequent to proteasomal protein degradation, tricorn generates small peptides, which are cleaved by f1 to yield single amino acids. we have solved the crystal structure of f1 with multiwavelength anomalous dispersion (mad) phasing at 1.8 a resolution. in addition to the conserved catalytic domain, the structure reveals a chiefly alpha-helical domain capping the catalytic triad. thus ...	2002	12374735
the influence of metabolic network structures and energy requirements on xanthan gum yields.	the metabolic network of xanthomonas campestris is complex since a number of cyclic pathways are present making simple stoichiometric yield predictions difficult. the influence of certain pathway configurations and the resulting variations in flux have been examined as regards the maximum yield potential of this bacteria for xanthan gum production. these predictions have been compared with experimental results showing that the strain employed is functioning close to its theoretical maximum as re ...	2002	12385717
isolation and characterization of a porin-like outer membrane protein from xanthomonas campestris pv. campestris.	xanthomonas campestris pv. campestris, a plant-associated pathogenic bacterium, is the causal agent of foliar spots and blights in crucifers. the major outer membrane protein, omp37, of 37 kda, has been identified, purified to homogeneity, and its characterization has also been carried out. native omp37 behaved as a trimer, as revealed by gel filtration and sds-page. ftir measurements revealed a high beta-structure content. the pore-forming ability of the purified omp37 was studied by the liposo ...	2002	12387570
isolation of a xanthomonas campestris strain with elevated beta-galactosidase activity for direct use of lactose in xanthan gum production.	to isolate a xanthomonas campestris strain that can use lactose directly for xanthan gum production.	2002	12390484
molecular characterization of spm-1, a novel metallo-beta-lactamase isolated in latin america: report from the sentry antimicrobial surveillance programme.	the gene encoding the metallo-beta-lactamase spm-1 was cloned from a genomic library of pseudomonas aeruginosa strain 48-1997 a. the insert carrying spm-1 possessed a gc content of 47%, indicating that it is of non-pseudomonas origin. upstream of spm-1 there is a small open reading frame (orf), which is homologous to the lysr family of proteins (69% identity to the lysr protein from salmonella enterica serovar typhimurium). downstream of spm-1 there is the start of an orf, the product of which s ...	2002	12407123
structures of the o-polysaccharide chains of the lipopolysaccharides of xanthomonas campestris pv phaseoli var fuscans gspb 271 and x campestris pv malvacearum gspb 1386 and gspb 2388.	o-polysaccharides of phytopathogenic bacteria xanthomonas campestris were isolated by mild acid degradation of the lipopolysaccharides and studied by sugar and methylation analysis, along with 1h and 13c nmr spectroscopy. the following structures of the repeating units of the polysaccharides of x. campestris pv. phaseoli var. fuscans gspb 271 (1). and x. campestris pv. malvacearum gspb 1386 and gspb 2388 (2). were established:the o-polysaccharides of x. campestris are structurally similar to tho ...	2002	12423950
enzymatic synthesis of alpha-arbutin by alpha-anomer-selective glucosylation of hydroquinone using lyophilized cells of xanthomonas campestris wu-9701.	alpha-arbutin, a useful cosmetic ingredient, was selectively synthesized by alpha-anomer-selective glucosylation of hydroquinone with maltose as a glucosyl donor using lyophilized cells of xanthomonas campestris wu-9701 as a biocatalyst. when 45 mm hydroquinone and 120 mg of lyophilized cells showing 11 nkat of alpha-glucosyl transfer activity were shaken in 2 ml of 10 mm h3bo3naohkcl buffer (ph 7.5) containing 1.2 m maltose at 40 degrees c, only one form of hydroquinone glucoside was selectivel ...	2002	16233209
enzymatic synthesis of l-menthyl alpha-maltoside and l-menthyl alpha-maltooligosides from l-menthyl alpha-glucoside by cyclodextrin glucanotransferase.	l-menthyl alpha-d-glucopyranosyl-(1-->4)-alpha-d-glucopyranoside (alpha-meng2), a novel glycoside of l-menthol, was synthesized enzymatically and its physicochemical properties were characterized. production of alpha-meng2 from l-menthyl alpha-d-glucopyranoside (alpha-meng) was attempted since we had already succeeded in the high-yield production of alpha-meng using a xanthomonas campestris enzyme (nakagawa h., et al. j. biosci. bioeng., 89, 138-144, 2000). through production tests on enzymes, i ...	2002	16233280
detection of the plant pathogenic bacterium xanthomonas campestris pv. campestris in seed extracts of brassica sp. applying fluorescent antibodies and flow cytometry.	xanthomonas campestris pv. campestris (xcc) is a seed-transmitted plant pathogenic bacterium that causes black rot of crucifers. seed lots and plants are screened for contamination with this pathogen using plating or serological assays. these methods, however, are time consuming and not very sensitive, respectively. therefore, flow cytometry (fcm) was evaluated as a tool for the rapid detection and quantification of xcc cells labeled with a mixture of specific fluorescein isothicyanate (fitc)-mo ...	2002	11813202
molecular analyses of the natural transformation machinery and identification of pilus structures in the extremely thermophilic bacterium thermus thermophilus strain hb27.	thermus thermophilus hb27, an extremely thermophilic bacterium, exhibits high competence for natural transformation. to identify genes of the natural transformation machinery of t. thermophilus hb27, we performed homology searches in the partially completed t. thermophilus genomic sequence for conserved competence genes. these analyses resulted in the detection of 28 open reading frames (orfs) exhibiting significant similarities to known competence proteins of gram-negative and gram-positive bac ...	2002	11823215
biosynthesis of a substituted cellulose from a mutant strain of xanthomonas campestris.	in xanthomonas campestris the genes involved in polysaccharide (xanthan) biosynthesis are located in a gene cluster (gum) of 16 kb. a tn5 insertion mutant with a reduced slimy phenotype has been characterized. this mutant failed to produce the pentasaccharide repeating-unit of xanthan. only three sugars were transferred to the prenyl phosphate intermediate. several lines of evidence suggested that the lipid-associated saccharide was the trisaccharide reducing end of the pentasaccharide from the ...	2002	11841812
two novel type iii-secreted proteins of xanthomonas campestris pv. vesicatoria are encoded within the hrp pathogenicity island.	the hrp type iii protein secretion system (ttss) is essential for pathogenicity of gram-negative plant pathogen xanthomonas campestris pv. vesicatoria. cdna-amplified fragment length polymorphism and reverse transcription-pcr analyses identified new genes, regulated by key hrp regulator hrpg, in the regions flanking the hrp gene cluster. sequence analysis revealed genes encoding hpag, a predicted leucine-rich repeat-containing protein, the lysozyme-like hpah protein, and xopa and xopd, which are ...	2002	11844763
mutation in the xanthomonas campestris xana gene required for synthesis of xanthan and lipopolysaccharide drastically reduces the efficiency of bacteriophage (phi)l7 adsorption.	(phi)l7 is a lytic phage infecting the gram-negative xanthomonas campestis pv. campestris, a plant pathogen. to study phage-host interaction, a (phi)l7-resistant mutant was isolated from strain xc17 by mini-tn5 transposition and designated ch7lr. ch7lr could not plate (phi)l7 in double-layered assay and formed turbid clearing zones when the cell lawn was dropped with a high titer of (phi)l7. sequence analysis showed that the mutated gene is xana coding for phosphoglucomutase/phosphomannomutase, ...	2002	11846409
genomewide identification of pseudomonas syringae pv. tomato dc3000 promoters controlled by the hrpl alternative sigma factor.	the ability of pseudomonas syringae pv. tomato dc3000 to parasitize tomato and arabidopsis thaliana depends on genes activated by the hrpl alternative sigma factor. to support various functional genomic analyses of dc3000, and specifically, to identify genes involved in pathogenesis, we developed a draft sequence of dc3000 and used an iterative process involving computational and gene expression techniques to identify virulence-implicated genes downstream of hrpl-responsive promoters. hypersensi ...	2002	11854524
induction of pepper cdna encoding a lipid transfer protein during the resistance response to tobacco mosaic virus.	pepper (capsicum annuum) plants exhibit hypersensitive response (hr) against infection by many tobamoviruses. a clone encoding a putative nonspecific lipid transfer protein (caltp1) was isolated by differential screening of a cdna library from resistant pepper leaves when inoculated with tobacco mosaic virus (tmv) pathotype p0. the predicted amino acid sequence of caltp1 is highly similar to that of the other plant ltps. southern blot analysis showed that a small gene family of ltp-related seque ...	2002	11855726
differential effectiveness of salicylate-dependent and jasmonate/ethylene-dependent induced resistance in arabidopsis.	salicylic acid (sa), jasmonic acid (ja), and ethylene (et) are each involved in the regulation of basal resistance against different pathogens. these three signals play important roles in induced resistance as well. sa is a key regulator of pathogen-induced systemic acquired resistance (sar), whereas ja and et are required for rhizobacteria-mediated induced systemic resistance (isr). both types of induced resistance are effective against a broad spectrum of pathogens. in this study, we compared ...	2002	11858171
synthesis of an xylosylated rhamnose pentasaccharide, the repeating unit of the o-chain polysaccharide of the lipopolysaccharide of xanthomonas campestris pv. begoniae gspb 525.	a xylosylated rhamnose pentasaccharide, alpha-l-rhap-(1-->3)-[beta-l-xylp-(1-->2)-]-alpha-l-rhap-(1-->3)-[beta-l-xylp-(1-->4)]-l-rhap, the repeating unit of the o-chain polysaccharide (ops) of the lipopolysaccharides of xanthomonas campestris pv. begoniae gspb 525 was synthesized by a highly regio- and stereoselective way. thus coupling of 1,2-o-ethylidene-beta-l-rhamnopyranose (1) with 2,3,4-tri-o-benzoyl-alpha-l-rhamnopyranosyl trichloroacetimidate (2) to give (1-->3)-linked disaccharide (3), ...	2002	11861012
genetic relationship among worldwide strains of xanthomonas causing canker in citrus species and design of new primers for their identification by pcr.	partial sequence analysis of the ribosomal operon in xanthomonas axonopodis allowed discrimination among strains causing the a, b, and c types of citrus bacterial canker (cbc) and quantification of the relationship of these organisms with other species and pathovars in the same genus. sets of primers based on sequence differences in the internally transcribed spacer and on a sequence from the plasmid gene ptha involved in virulence were designed for specific identification of xanthomonads causin ...	2002	11872476
effects of t4 lysozyme release from transgenic potato roots on bacterial rhizosphere communities are negligible relative to natural factors.	rhizosphere bacterial communities of two transgenic potato lines which produce t4 lysozyme for protection against bacterial infections were analyzed in comparison to communities of wild-type plants and transgenic controls not harboring the lysozyme gene. rhizosphere samples were taken from young, flowering, and senescent plants at two field sites in three consecutive years. the communities were characterized in a polyphasic approach. cultivation-dependent methods included heterotrophic plate cou ...	2002	11872484
reduction of olive knot disease by a bacteriocin from pseudomonas syringae pv. ciccaronei.	a bacteriocin produced by pseudomonas syringae pv. ciccaronei, used at different purification levels and concentrations in culture and in planta, inhibited the multiplication of p. syringae subsp. savastanoi, the causal agent of olive knot disease, and affected the epiphytic survival of the pathogen on the leaves and twigs of treated olive plants. treatments with bacteriocin from p. syringae pv. ciccaronei inhibited the formation of overgrowths on olive plants caused by p. syringae subsp. savast ...	2002	11872493
mutational analysis of the tonb1 energy coupler of pseudomonas aeruginosa.	siderophore-mediated iron transport in pseudomonas aeruginosa is dependent upon the cytoplasmic membrane-associated tonb1 energy coupling protein for activity. to assess the functional significance of the various regions of this molecule and to identify functionally important residues, the tonb1 gene was subjected to site-directed mutagenesis, and the influence on iron acquisition was determined. the novel n-terminal extension of tonb1, which is absent in all other examples of tonb, was required ...	2002	11872700
a two-component regulator mediates population-density-dependent expression of the bradyrhizobium japonicum nodulation genes.	bradyrhizobium japonicum nod gene expression was previously shown to be population density dependent. induction of the nod genes is highest at low culture density and repressed at high population densities. this repression involves both nola and nodd2 and is mediated by an extracellular factor found in b. japonicum conditioned medium. nola and nodd2 expression is maximal at high population densities. we demonstrate here that a response regulator, encoded by nwsb, is required for the full express ...	2002	11872728
age-related resistance in arabidopsis is a developmentally regulated defense response to pseudomonas syringae.	age-related resistance (arr) has been observed in a number of plant species; however, little is known about the biochemical or molecular mechanisms involved in this response. arabidopsis becomes more resistant, or less susceptible, to virulent pseudomonas syringae (pv tomato or maculicola) as plants mature (in planta bacterial growth reduction of 10- to 100-fold). an arr-like response also was observed in response to certain environmental conditions that accelerate arabidopsis development. arr o ...	2002	11884688
molecular analysis of the gene encoding a novel chitin-binding protease from alteromonas sp. strain o-7 and its role in the chitinolytic system.	alteromonas sp. strain o-7 secretes several proteins in response to chitin induction. we have found that one of these proteins, designated apriv, is a novel chitin-binding protease involved in chitinolytic activity. the gene encoding apriv (apriv) was cloned in escherichia coli. dna sequencing analysis revealed that the open reading frame of apriv encoded a protein of 547 amino acids with a calculated molecular mass of 57,104 da. apriv is a modular enzyme consisting of five domains: the signal s ...	2002	11889092
the cytochrome c maturation locus of legionella pneumophila promotes iron assimilation and intracellular infection and contains a strain-specific insertion sequence element.	previously, we obtained a legionella pneumophila mutant, nu208, that is hypersensitive to iron chelators when grown on standard legionella media. here, we demonstrate that nu208 is also impaired for growth in media that simply lack their iron supplement. the mutant was not, however, impaired for the production of legiobactin, the only known l. pneumophila siderophore. importantly, nu208 was also highly defective for intracellular growth in human u937 cell macrophages and hartmannella and acantha ...	2002	11895946
characterization and toxicity of amanita cokeri extract.	the nonprotein amino acids 2-amino-3-cyclopropylbutanoic acid and 2-amino-5-chloro-4-pentenoic acid were isolated from the mushroom amanita cokeri. the cyclopropyl amino acid is toxic to the fungus cercospora kikuchii, the arthropod oncopeltus fasciatus (milk weed bug), and the bacteria agrobacterium tumefaciens, erwinia amylovora, and xanthomonas campestris. toxicity to bacteria was reversible by addition of isoleucine to the medium. no toxicity was observed for 2-amino-5-chloro-4-pentenoic aci ...	2002	11925071
genetic control of quorum-sensing signal turnover in agrobacterium tumefaciens.	a signal turnover system is an essential component of many genetic regulatory mechanisms. the best-known example is the ubiquitin-dependent protein degradation system that exists in many organisms. we found that agrobacterium tumefaciens adopts a unique signal turnover system to control exiting from a quorum-sensing mode. a. tumefaciens regulates ti plasmid conjugal transfer by a quorum-sensing signal, n-3-oxo-octanoyl homoserine lactone (3oc8hsl), also known as agrobacterium autoinducer. by usi ...	2002	11930013
phylogenetic analysis of xanthomonas species based upon 16s-23s rdna intergenic spacer sequences.	phylogenetic relationships of 17 species of xanthomonas were assessed based on analysis of 16s-23s rdna intergenic spacer (its) sequences; a higher level of resolution was obtained than that revealed by 16s rdna analysis. its sequences varied in size from 492 to 578 nt within the genus and the similarity among sequences ranged from 63 to 99%. major differences were found for the hyacinthi group, which included xanthomonas albilineans, xanthomonas hyacinthi, xanthomonas sacchari, xanthomonas thei ...	2002	11931143
xpsg, the major pseudopilin in xanthomonas campestris pv. campestris, forms a pilus-like structure between cytoplasmic and outer membranes.	gspg, -h, -i, -j and -k proteins are members of the pseudopilin family. they are the components required for the type ii secretion pathway, which translocates proteins across the outer membrane of gram-negative bacteria to the extracellular milieu. they were predicted to form a pilus-like structure, and this has been shown for pulg of klebsiella oxytoca by using electron microscopy. in the present study, we performed biochemical analyses of the xpsg protein of xanthomonas campestris pv. campestr ...	2002	11931643
functional analysis of hrpf, a putative type iii translocon protein from xanthomonas campestris pv. vesicatoria.	type iii secretion systems (ttsss) are specialized protein transport systems in gram-negative bacteria which target effector proteins into the host cell. the ttss of the plant pathogen xanthomonas campestris pv. vesicatoria, encoded by the hrp (hypersensitive reaction and pathogenicity) gene cluster, is essential for the interaction with the plant. one of the secreted proteins is hrpf, which is required for pathogenicity but dispensable for type iii secretion of effector proteins in vitro, sugge ...	2002	11948151
ocatin. a novel tuber storage protein from the andean tuber crop oca with antibacterial and antifungal activities.	the most abundant soluble tuber protein from the andean crop oca (oxalis tuberosa mol.), named ocatin, has been purified and characterized. ocatin accounts for 40% to 60% of the total soluble oca tuber proteins, has an apparent molecular mass of 18 kd and an isoelectric point of 4.8. this protein appears to be found only in tubers and is accumulated only within the cells of the pith and peridermis layers (peel) of the tuber as it develops. ocatin inhibits the growth of several phytopathogenic ba ...	2002	11950978
involvement of caspase-3-like protein in rapid cell death of xanthomonas.	xanthomonas campestris pv. glycines strain am2 (xcgam2), the aetiological agent of bacterial pustule disease of soybean, as well as some other strains of xanthomonas including x. campestris pv. malvacearum ncim 2310 and x. campestris ncim 2961, exhibited post-exponential rapid cell death (rcd) in luria-bertani (lb) medium. rcd was not displayed by xanthomonas strains while growing in starch medium. addition of starch to lb culture of xcgam2 at any point of incubation during the exponential growt ...	2002	11972778
the ohrr repressor senses organic hydroperoxides by reversible formation of a cysteine-sulfenic acid derivative.	reactive oxygen species induce the expression of detoxification and repair genes critical for life in an aerobic environment. bacterial factors that sense reactive oxygen species use either thiol-disulfide exchange reactions (oxyr, rsra) or redox labile 2fe-2s clusters (soxr). we demonstrate that the reduced form of bacillus subtilis ohrr binds cooperatively to two adjacent inverted repeat sequences in the ohra control region and thereby represses transcription. in the presence of organic hydrop ...	2002	11983871
a fadd mutant of sinorhizobium meliloti shows multicellular swarming migration and is impaired in nodulation efficiency on alfalfa roots.	swarming is a form of bacterial translocation that involves cell differentiation and is characterized by a rapid and co-ordinated population migration across solid surfaces. we have isolated a tn5 mutant of sinorhizobium meliloti gr4 showing conditional swarming. swarm cells from the mutant strain qs77 induced on semi-solid minimal medium in response to different signals are hyperflagellated and about twice as long as wild-type cells. genetic and physiological characterization of the mutant stra ...	2002	11985715
genetic organization of the lexa, reca and recx genes in xanthomonas campestris.	a gene cluster containing lexa, reca and recx genes was previously identified and characterized in xanthomonas campestris pathovar citri (x. c. pv. citri). we have now cloned and sequenced the corresponding regions in the xanthomonas campestris pv. campestris (x. c. pv. campestris) and xanthomonas oryzae pathovar oryzae (x. o. pv. oryzae) chromosome. sequence analysis of these gene clusters showed significant homology to the previously reported lexa, reca and recx genes. the genetic linkage and ...	2002	12007798
comparison of the genomes of two xanthomonas pathogens with differing host specificities.	the genus xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the proteobacteria. xanthomonas axonopodis pv. citri (xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. xanthomonas campestris pv. campestris (xcc) causes black rot, which affects crucifers such a ...	2002	12024217
osmoregulated periplasmic glucans of the free-living photosynthetic bacterium rhodobacter sphaeroides.	the osmoregulated periplasmic glucans (opgs) produced by rhodobacter sphaeroides, a free-living organism, were isolated by trichloracetic acid treatment and gel permeation chromatography. compounds obtained were characterized by compositional analysis, matrix-assisted laser desorption ionization mass spectrometry and nuclear magnetic resonance. r. sphaeroides predominantly synthesizes a cyclic glucan containing 18 glucose residues that can be substituted by one to seven succinyl esters residues ...	2002	12027884
genomewide identification of proteins secreted by the hrp type iii protein secretion system of pseudomonas syringae pv. tomato dc3000.	the ability of pseudomonas syringae pv. tomato dc3000 to be pathogenic on plants depends on the hrp (hypersensitive response and pathogenicity) type iii protein secretion system and the effector proteins it translocates into plant cells. through iterative application of experimental and computational techniques, the dc3000 effector inventory has been substantially enlarged. five homologs of known avirulence (avr) proteins and five effector candidates, encoded by genes with putative hrp promoters ...	2002	12032338
a novel type of conserved dna-binding domain in the transcriptional regulators of the algr/agra/lytr family.	sequence analysis of bacterial genomes revealed a novel dna-binding domain. this domain is found in several response regulators of the two-component signal transduction system, such as pseudomonas aeruginosa algr, involved in the regulation of alginate biosynthesis and in the pathogenesis of cystic fibrosis; clostridium perfringens virr, a regulator of virulence factors, and in several regulators of bacteriocin biosynthesis, previously unified in the agra/come family. most of the transcriptional ...	2002	12034833
rpff mutants of xanthomonas oryzae pv. oryzae are deficient for virulence and growth under low iron conditions.	xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. in the related bacterium xanthomonas campestris pv. campestris, the rpff gene is involved in production of a diffusible extracellular factor (dsf) that positively regulates synthesis of virulence-associated functions like extracellular polysaccharide (eps) and extracellular enzymes. transposon insertions in the rpff homolog of x. oryzae pv. oryzae are deficient for virulence and production of a dsf but are pro ...	2002	12036277
characterization of unusual bacteria isolated from respiratory secretions of cystic fibrosis patients and description of inquilinus limosus gen. nov., sp. nov.	using a polyphasic approach (including cellular protein and fatty acid analysis, biochemical characterization, 16s ribosomal dna sequencing, and dna-dna hybridizations), we characterized 51 bacterial isolates recovered from respiratory secretions of cystic fibrosis (cf) patients. our analyses showed that 24 isolates belong to taxa that have so far not (or only rarely) been reported from cf patients. these taxa include acinetobacter sp., bordetella hinzii, burkholderia fungorum, comamonas testost ...	2002	12037065
molecular identification of family 38 alpha-mannosidase of bacillus sp. strain gl1, responsible for complete depolymerization of xanthan.	when cells of bacillus sp. strain gl1 were grown in a medium containing xanthan as a carbon source, alpha-mannosidase exhibiting activity toward p-nitrophenyl-alpha-d-mannopyranoside (pnp-alpha-d-man) was produced intracellularly. the 350-kda alpha-mannosidase purified from a cell extract of the bacterium was a trimer comprising three identical subunits, each with a molecular mass of 110 kda. the enzyme hydrolyzed pnp-alpha-d-man (km = 0.49 mm) and d-mannosyl-(alpha-1,3)-d-glucose most efficient ...	2002	12039727
oric region and replication termination site, dif, of the xanthomonas campestris pv. campestris 17 chromosome.	a 13-kb dna fragment containing oric and the flanking genes thdf, orf900, yidc, rnpa, rpmh, oric, dnaa, dnan, recf, and gyrb was cloned from the gram-negative plant pathogen xanthomonas campestris pv. campestris 17. these genes are conserved in order with other eubacterial oric genes and code for proteins that share high degrees of identity with their homologues, except for orf900, which has a homologue only in xylella fastidiosa. the dnaa/dnan intergenic region (273 bp) identified to be the min ...	2002	12039751
genetic locus encoding functions involved in biosynthesis and outer membrane localization of xanthomonadin in xanthomonas oryzae pv. oryzae.	xanthomonadins are membrane-bound, brominated, aryl-polyene pigments specific to the genus xanthomonas. we have characterized a genetic locus (pig) from xanthomonas oryzae pv. oryzae which contains four open reading frames (orfs) that are essential for xanthomonadin production. three of these orfs are homologous to acyl carrier proteins, dehydratases, and acyl transferases, suggesting a type ii polyketide synthase pathway for xanthomonadin biosynthesis. the fourth orf has no homologue in the dat ...	2002	12057948
the rhizobium etli cyac product: characterization of a novel adenylate cyclase class.	adenylate cyclases (acs) catalyze the formation of 3',5'-cyclic amp (camp) from atp. a novel ac-encoding gene, cyac, was isolated from rhizobium etli by phenotypic complementation of an escherichia coli cya mutant. the functionality of the cyac gene was corroborated by its ability to restore camp accumulation in an e. coli cya mutant. further, overexpression of a male::cyac fusion protein allowed the detection of significant ac activity levels in cell extracts of an e. coli cya mutant. cyac is u ...	2002	12057950
ppi1: a novel pathogen-induced basic region-leucine zipper (bzip) transcription factor from pepper.	we have isolated a full-length cdna, ppi1 (pepper-pmmv interaction 1), encoding a novel basic region-leucine zipper (bzip) dna-binding protein, from expressed sequence tags differentially expressed in capsicum chinense p1257284 infected with pepper mild mottle virus (pmmv). ppi1 encodes a predicted protein of 170 amino acids and contains a putative dna-binding domain that shares significant amino acid identity with acgt-binding domains of members of the bzip dna-binding protein family. ppi1 was ...	2002	12059102
direct biochemical evidence for type iii secretion-dependent translocation of the avrbs2 effector protein into plant cells.	the calmodulin-dependent adenylate cyclase domain (cya) of the bordetella pertussis cyclolysin was used as a reporter protein to study the direct translocation of the xanthomonas effector protein, avrbs2, into the plant host cell. adenylate cyclase activity (production of camp) depends on the presence of eukaryotic plant calmodulin and is only active after translocation from the prokaryotic cell into the eukaryotic plant cell. here, we show that infection of pepper plants by xanthomonas campestr ...	2002	12060777
transcription of xanthomonas campestris prt1 gene encoding protease 1 increases during stationary phase and requires global transcription factor clp.	xanthomonas campestris pv. campestris produces three proteases, prt1, prt2, and prt3, the first two of which are involved in pathogenicity. in this study, nucleotide a 84 nt upstream of the prt1 start codon, which is 8 nt downstream of the -10 sequence, was determined as the transcription start site by the 5(') race (rapid amplification of cdna ends) method. using pprt1-lacz transcriptional fusion constructs for assays, several interesting characteristics of prt1 promoter were revealed. the expr ...	2002	12083764
gene discovery within the planctomycete division of the domain bacteria using sequence tags from genomic dna libraries.	the planctomycetes comprise a distinct group of the domain bacteria, forming a separate division by phylogenetic analysis. the organization of their cells into membrane-defined compartments including membrane-bounded nucleoids, their budding reproduction and complete absence of peptidoglycan distinguish them from most other bacteria. a random sequencing approach was applied to the genomes of two planctomycete species, gemmata obscuriglobus and pirellula marina, to discover genes relevant to thei ...	2002	12093378
altering plant-microbe interaction through artificially manipulating bacterial quorum sensing.	many bacteria regulate diverse physiological processes in concert with their population size. bacterial cell-to-cell communication utilizes small diffusible signal molecules, which the bacteria both produce and perceive. the bacteria couple gene expression to cell density by eliciting a response only when the signalling molecules reach a critical threshold (a point at which the population is said to be 'quorate'). the population as a whole is thus able to modify its behaviour as a single unit. a ...	2002	12096736
molecular cloning and tissue distribution of mammalian l-threonine 3-dehydrogenases.	in mammals, l-threonine is an indispensable amino acid. the conversion of l-threonine to glycine occurs through a two-step biochemical pathway involving the enzymes l-threonine 3-dehydrogenase and 2-amino-3-ketobutyrate coenzyme a ligase. the l-threonine 3-dehydrogenase enzyme has been purified and characterised, but the l-threonine 3-dehydrogenase gene has not previously been identified in mammals.	2002	12097150
the role of ethylene and wound signaling in resistance of tomato to botrytis cinerea.	ethylene, jasmonate, and salicylate play important roles in plant defense responses to pathogens. to investigate the contributions of these compounds in resistance of tomato (lycopersicon esculentum) to the fungal pathogen botrytis cinerea, three types of experiments were conducted: (a) quantitative disease assays with plants pretreated with ethylene, inhibitors of ethylene perception, or salicylate; (b) quantitative disease assays with mutants or transgenes affected in the production of or the ...	2002	12114587
the xanthomonas type iii effector protein avrbs3 modulates plant gene expression and induces cell hypertrophy in the susceptible host.	xanthomonas campestris pv. vesicatoria bacteria expressing the type iii effector protein avrbs3 induce a hypersensitive response in pepper plants carrying the resistance gene bs3. here, we report that infection of susceptible pepper and tomato plants leads to an avrbs3-dependent hypertrophy of the mesophyll tissue. agrobacterium-mediated transient expression of the avrbs3 gene in tobacco and potato plants resulted in a similar phenotype. induction of hypertrophy was shown to depend on the repeat ...	2002	12118879
a r2r3-myb gene, atmyb30, acts as a positive regulator of the hypersensitive cell death program in plants in response to pathogen attack.	hypersensitive response (hr) is a programmed cell death that is commonly associated with disease resistance in plants. among the different hr-related early induced genes, the atmyb30 gene is specifically, rapidly, and transiently expressed during incompatible interactions between arabidopsis and bacterial pathogens. its expression was also shown to be deregulated in arabidopsis mutants affected in the control of cell death initiation. here, we demonstrate that overexpression in arabidopsis and t ...	2002	12119395
ubiquitin ligase-associated protein sgt1 is required for host and nonhost disease resistance in plants.	homologues of the yeast ubiquitin ligase-associated protein sgt1 are required for disease resistance in plants mediated by nucleotide-binding site/leucine-rich repeat (nbs-lrr) proteins. here, by silencing sgt1 in nicotiana benthamiana, we extend these findings and demonstrate that sgt1 has an unexpectedly general role in disease resistance. it is required for resistance responses mediated by nbs-lrr and other r proteins in which pathogen-derived elicitors are recognized either inside or outside ...	2002	12119413
a gene encoding stellacyanin is induced in capsicum annuum by pathogens, methyl jasmonate, abscisic acid, wounding, drought and salt stress.	a stellacyanin cdna clone (caslp1) was isolated from a pepper cdna library from hypersensitive response (hr) lesions of leaves infected with an avirulent strain of xanthomonas campestris pv. vesicatoria. the deduced amino acid sequences of caslp1 are homologous to those of stellacyanins from cucumber, maize, pea and arabidopsis. the caslp1 mrna was not constitutively expressed in all organs of pepper, but strongly induced and accumulated in pepper tissues infected with x. campestris pv. vesicato ...	2002	12121461
a reversibly dissociable ternary complex formed by xpsl, xpsm and xpsn of the xanthomonas campestris pv. campestris type ii secretion apparatus.	the cytoplasmic membrane proteins xpsl, xpsm and xpsn are components required for type ii secretion in xanthomonas campestris pv. campestris. we performed metal-chelating chromatography to partially purify the his(6)-tagged xpsm (xpsmh)-containing complex. immunoblot analysis revealed that both xpsl and xpsn co-eluted with xpsmh. the co-fractionated xpsl and xpsn proteins co-immune precipitated with each other, suggesting the existence of an xpsl-xpsm-xpsn complex. ternary complex formation does ...	2002	12123417
the superantigen gene ypm is located in an unstable chromosomal locus of yersinia pseudotuberculosis.	yersinia pseudotuberculosis produces ypm (y. pseudotuberculosis-derived mitogen), a superantigenic toxin that exacerbates the virulence of the bacterium in vivo. to date, three alleles of the superantigen gene (ypma, ypmb, and ypmc) have been described. these genes are not found in all y. pseudotuberculosis strains and have a low gc content, suggesting their location on mobile genetic elements. to elucidate this question, the genetic environment of the superantigen-encoding genes was characteriz ...	2002	12142419
homologs of the rml enzymes from salmonella enterica are responsible for dtdp-beta-l-rhamnose biosynthesis in the gram-positive thermophile aneurinibacillus thermoaerophilus dsm 10155.	the glycan chains of the surface layer (s-layer) glycoprotein from the gram-positive, thermophilic bacterium aneurinibacillus (formerly bacillus) thermoaerophilus strain dsm 10155 are composed of l-rhamnose- and d-glycero-d-manno-heptose-containing disaccharide repeating units which are linked to the s-layer polypeptide via core structures that have variable lengths and novel o-glycosidic linkages. in this work we investigated the enzymes involved in the biosynthesis of thymidine diphospho-l-rha ...	2002	12147463
comparative genomic analysis of plant-associated bacteria.	this review deals with a comparative analysis of seven genome sequences from plant-associated bacteria. these are the genomes of agrobacterium tumefaciens, mesorhizobium loti, sinorhizobium meliloti, xanthomonas campestris pv campestris, xanthomonas axonopodis pv citri, xylella fastidiosa, and ralstonia solanacearum. genome structure and the metabolism pathways available highlight the compromise between the genome size and lifestyle. despite the recognized importance of the type iii secretion sy ...	2002	12147758
antibiotic use in plant agriculture.	antibiotics have been used since the 1950s to control certain bacterial diseases of high-value fruit, vegetable, and ornamental plants. today, the antibiotics most commonly used on plants are oxytetracycline and streptomycin. in the usa, antibiotics applied to plants account for less than 0.5% of total antibiotic use. resistance of plant pathogens to oxytetracycline is rare, but the emergence of streptomycin-resistant strains of erwinia amylovora, pseudomonas spp., and xanthomonas campestris has ...	2002	12147767
[cloning of xanthomonas campestris pv. campestris pathogenicity-related gene sequences by tail-pcr].	southern blot analysis with probe from mini-tn5 gfp-km transposon indicated that 5 non-pathogenic mutants which were generated by insertion of mini-tn5 gfp-km mutagenesis contained a single copy of the transposon. using genomic dna of each mutant as a template, tail-pcr was performed with seven arbitrary degenerate (ad) primers pairing with 3 nested specific primers designed based on the sequence of gfp toward outside in mini-tn5 gfp-km. after 3-step pcr reactions, the flanking sequence of each ...	2002	12148280
rapd-based genetic linkage maps of yellow passion fruit (passiflora edulis sims. f. flavicarpa deg.).	a single cross between two clones of passion fruit (passiflora edulis sims. f. flavicarpa deg., 2n = 18) was selected for genetic mapping. the mapping population was composed of 90 f1 plants derived from a cross between 'iapar 123' (female parent) and 'iapar 06' (male parent). a total of 380 rapd primers were analyzed according to two-way pseudo-testcross mapping design. the linkage analysis was performed using mapmaker version 3.0 with lod 4.0 and a maximum recombination fraction (theta) of 0.3 ...	2002	12175070
nmr and ms evidences for a random assembled o-specific chain structure in the lps of the bacterium xanthomonas campestris pv. vitians. a case of unsystematic biosynthetic polymerization.	xanthomonas campestris pv. vitians is a gram-negative plant-associated bacterium that acts as causative agent of bacterial leaf spot and headrot in lettuce. the lipopolysaccharide of this bacterium is suspected to be an important molecule for adhesion to and infection of the plants. the lipopolysaccharide has been isolated from the phenol phase and the o-specific chain characterized by compositional analysis, high field nmr and maldi-tof ms. it consists of a nonrepetitive branched polysaccharide ...	2002	12199696
biodegradation of the polyketide toxin cercosporin.	cercosporin is a non-host-specific polyketide toxin produced by many species of plant pathogens belonging to the genus cercospora. this red-pigmented, light-activated toxin is an important pathogenicity determinant for cercospora species. in this study, we screened 244 bacterial isolates representing 12 different genera for the ability to degrade cercosporin. cercosporin degradation was determined by screening for the presence of cleared zones surrounding colonies on cercosporin-containing cultu ...	2002	12200262
assessment of the importance of similarity in carbon source utilization profiles between the biological control agent and the pathogen in biological control of bacterial speck of tomato.	bacterial speck of tomato, caused by pseudomonas syringae pv. tomato, was used to determine whether similarity in carbon source utilization between a preemptive biological control agent and the pathogen was significant in determining the ability of the bacterium to suppress disease. similarity in carbon source utilization was quantified as the ratio of the number of tomato carbon sources utilized in vitro by the biological control agent to the number of tomato carbon sources utilized in vitro by ...	2002	12200291
construction and characterization of a prou-gfp transcriptional fusion that measures water availability in a microbial habitat.	we constructed and characterized a transcriptional fusion that measures the availability of water to a bacterial cell. this fusion between the prou promoter from escherichia coli and the reporter gene gfp was introduced into strains of e. coli, pantoea agglomerans, and pseudomonas syringae. the prou-gfp fusion in these bacterial biosensor strains responded in a quantitative manner to water deprivation caused by the presence of nacl, na(2)so(4), kcl, or polyethylene glycol (molecular weight, 8000 ...	2002	12200319
gene disruption by homologous recombination in the xylella fastidiosa citrus variegated chlorosis strain.	mutagenesis by homologous recombination was evaluated in xylella fastidiosa by using the bga gene, coding for beta-galactosidase, as a model. integration of replicative plasmids by homologous recombination between the cloned truncated copy of bga and the endogenous gene was produced by one or two crossover events leading to beta-galactosidase mutants. a promoterless chloramphenicol acetyltransferase gene was used to monitor the expression of the target gene and to select a cvab mutant.	2002	12200328
whole-genome comparative analysis of three phytopathogenic xylella fastidiosa strains.	xylella fastidiosa (xf) causes wilt disease in plants and is responsible for major economic and crop losses globally. owing to the public importance of this phytopathogen we embarked on a comparative analysis of the complete genome of xf pv citrus and the partial genomes of two recently sequenced strains of this species: xf pv almond and xf pv oleander, which cause leaf scorch in almond and oleander plants, respectively. we report a reanalysis of the previously sequenced xf 9a5c (cvc, citrus) st ...	2002	12205291
complete characterisation of tn5530 from burkholderia cepacia strain 2a (pijb1) and studies of 2,4-dichlorophenoxyacetate uptake by the organism.	the complete genetic characterisation of tn5530 in burkholderia cepacia strain 2a (pijb1) has been accomplished, indicating that it is a tn3-like transposon with a complex structure bearing operons for the catabolism of 2,4-dichlorophenoxyacetate (2,4-d) and malonate. tn5530 is terminated at both ends by the is1071::is1471 element and the 2,4-d- and malonate-dissimilatory operons are separated by a region encoding a puta and lrp gene and a gene encoding a chloride channel protein. the chloride c ...	2002	12206751
type iii secretion systems and the evolution of mutualistic endosymbiosis.	the view that parasites can develop cooperative symbiotic relationships with their hosts is both appealing and widely held; however, there is no molecular genetic evidence of such a transition. here we demonstrate that a mutualistic bacterial endosymbiont of grain weevils maintains and expresses inv/spa genes encoding a type iii secretion system homologous to that used for invasion by bacterial pathogens. phylogenetic analyses indicate that inv/spa genes were present in presymbiotic ancestors of ...	2002	12213957
role of oxyr as a peroxide-sensing positive regulator in streptomyces coelicolor a3(2).	genes encoding a homolog of escherichia coli oxyr (oxyr) and an alkyl hydroperoxide reductase system (ahpc and ahpd) have been isolated from streptomyces coelicolor a3(2). the ahpc and ahpd genes constitute an operon transcribed divergently from the oxyr gene. expression of both ahpcd and oxyr genes was maximal at early exponential phase and decreased rapidly as cells entered mid-exponential phase. overproduction of oxyr in streptomyces lividans conferred resistance against cumene hydroperoxide ...	2002	12218006
multidrug pump inhibitors uncover remarkable activity of plant antimicrobials.	plant antimicrobials are not used as systemic antibiotics at present. the main reason for this is their low level of activity, especially against gram-negative bacteria. the reported mic is often in the range of 100 to 1,000 micro g/ml, orders of magnitude higher than those of common broad-spectrum antibiotics from bacteria or fungi. major plant pathogens belong to the gram-negative bacteria, which makes the low level of activity of plant antimicrobials against this group of microorganisms puzzl ...	2002	12234835
a hot pepper cdna encoding ascorbate peroxidase is induced during the incompatible interaction with virus and bacteria.	capsicum annuum l. is infected by a number of viruses, including the tobacco mosaic virus (tmv). to study the defense-related genes that are induced by tmv in hot peppers, the pepper plant, which is susceptible to p1.2 but resistant to the p0 pathotype of tmv, was inoculated with tmv-p0. differential screening isolated the genes that were specifically up- or down-regulated during the hypersensitive response (hr). the caapx1 cdna clone that putatively encodes a polypeptide of cytosolic ascorbate ...	2002	12243356
heca, a member of a class of adhesins produced by diverse pathogenic bacteria, contributes to the attachment, aggregation, epidermal cell killing, and virulence phenotypes of erwinia chrysanthemi ec16 on nicotiana clevelandii seedlings.	erwinia chrysanthemi is representative of a broad class of bacterial pathogens that are capable of inducing necrosis in plants. the e. chrysanthemi ec16 heca gene predicts a 3,850-aa member of the bordetella pertussis filamentous hemagglutinin family of adhesins. a hecatn7 mutant was reduced in virulence on nicotiana clevelandii seedlings after inoculation without wounding. epifluorescence and confocal laser-scanning microscopy observations of heca and wild-type cells expressing the green fluore ...	2002	12271135
inheritance of race-specific resistance to xanthomonas campestris pv. campestris in brassica genomes.	abstract the inheritance of resistance to three xanthomonas campestris pv. campestris races was studied in crosses between resistant and susceptible lines of brassica oleracea (c genome), b. carinata (bc genome), and b. napus (ac genome). resistance to race 3 in the b. oleracea doubled haploid line boh 85c and in pi 436606 was controlled by a single dominant locus (xca3). resistance to races 1 and 3 in the b. oleracea line badger inbred-16 was quantitative and recessive. strong resistance to rac ...	2002	18944224
four near-isogenic lines of cotton with different genes for bacterial blight resistance.	abstract the development and genetic characterization of four near-isogenic lines (nils) of cotton (gossypium hirsutum) is described herein. each line contains a single, but different, gene for resistance to bacterial blight caused by xanthomonas campestris pv. malvacearum. the lines were derived using at least six backcrosses to the susceptible recurrent parent 'acala 44', followed by single plant-progeny row selection for uniformity. the nils are homozygous for the b(2), b(4), b(in), or b(7) g ...	2002	18943887
sources and origin of resistance to xanthomonas campestris pv. campestris in brassica genomes.	abstract two hundred and seventy-six accessions of mainly brassica spp. were screened for resistance to xanthomonas campestris pv. campestris races. in brassica oleracea (c genome), the majority of accessions were susceptible to all races, but 43% showed resistance to one or more of the rare races (2, 3, 5, and 6) and a single accession showed partial resistance to races 1, 3, 5, and 6. further searches for resistance to races 1 and 4, currently the most important races worldwide, and race 6, th ...	2002	18944146
mob psychology.		2002	11807045
type ii secretion and pathogenesis.		2001	11349009
type iii secretion and in planta recognition of the xanthomonas avirulence proteins avrbs1 and avrbst.	summary the hrp gene cluster of the plant pathogen xanthomonas campestris pv. vesicatoria (xcv) encodes a type iii secretion system required for the delivery of virulence and avirulence proteins into the plant. some of these effector proteins, e.g. avrbs1 and avrbst, are recognized by pepper plants carrying corresponding resistance genes, triggering the hypersensitive reaction (hr). in this study, epitope tagged avrbs1 and avrbst proteins were detected in culture supernatants only in the presenc ...	2001	20573017
antimicrobial activity of culture filtrate of bacillus amyloliquefaciens rc-2 isolated from mulberry leaves.	abstract a potential antagonist, bacillus amyloliquefaciens strain rc-2, against colletotrichum dematium, mulberry anthracnose fungus, was obtained from healthy mulberry leaves by in vitro and in vivo screening techniques. application of culture filtrate of rc-2 inhibited disease on mulberry leaves, indicating that suppression was due to antifungal compounds in the filtrate. development of mulberry anthracnose on mulberry leaves was inhibited only when the culture filtrate was applied before fun ...	2001	18944392
identification and origin of xanthomonas campestris pv. campestris races and related pathovars.	abstract one hundred sixty-four isolates of xanthomonas campestris pv. campestris and other x. campestris pathovars known to infect cruciferous hosts (x. campestris pvs. aberrans, raphani, armoraciae, and incanae) were inoculated onto a differential series of brassica spp. to determine both pathogenicity to brassicas and race. of these, 144 isolates were identified as x. campestris pv. campestris and grouped into six races, with races 1 (62%) and 4 (32%) being predominant. other races were rare. ...	2001	18943594
characterization and antimicrobial activity of erbium(iii) complexes of c-3 substituted 2-hydroxy-1,4-naphthalenedione-1-oxime derivatives.	erbium(iii) complexes of 2-hydroxy-l,4-naphthalenedione-1-oxime and its c-3 substituted derivatives are synthesized and characterized by elemental analysis, thermogravimetric analysis, infrared spectroscopy, magnetic susceptibility measurements 2-hydroxy-1,4-naphthalenedione-1-oxime derivatives are analysed using (1)h and (13)c nmr spectroscopy. the molecular composition of the synthesized complexes is found to be [ml(3)(h(2)o)(2)]. the antimicrobial activity of these complexes is determined by ...	2001	18475990
molecular characterization and expression of the recx gene of xanthomonas campestris pv. citri.	two genes important in dna repair, reca and lexa, were recently identified in xanthomonas campestris pathovar citri (x.c. pv. citri). an open reading frame located immediately downstream of lexa and reca has now been isolated from this pathovar and characterized. this 486-bp open reading frame encodes a protein of 162 amino acids and shares substantial sequence similarity with recx of other bacterial species. the x.c. pv. citri recx protein was overexpressed in escherichia coli and purified; sds ...	2001	11178726
ethylene-dependent salicylic acid regulates an expanded cell death response to a plant pathogen.	the molecular events associated with susceptible plant responses to disease-causing organisms are not well understood. we have previously shown that ethylene-insensitive tomato plants infected with xanthomonas campestris pv. vesicatoria have greatly reduced disease symptoms relative to wild-type cultivars. here we show that salicylic acid (sa) is also an important component of the susceptible disease response. sa accumulates in infected wild-type tissues and is correlated with necrosis but does ...	2001	11208023
exchange of xcp (gsp) secretion machineries between pseudomonas aeruginosa and pseudomonas alcaligenes: species specificity unrelated to substrate recognition.	pseudomonas aeruginosa and pseudomonas alcaligenes are gram-negative bacteria that secrete proteins using the type ii or general secretory pathway, which requires at least 12 xcp gene products (xcpa and xcpp to -z). despite strong conservation of this secretion pathway, gram-negative bacteria usually cannot secrete exoproteins from other species. based on results obtained with erwinia, it has been proposed that the xcpp and/or xcpq homologs determine this secretion specificity (m. linderberg, g. ...	2001	11208795
the evolutionary history of chromosomal super-integrons provides an ancestry for multiresistant integrons.	integrons are genetic elements that acquire and exchange exogenous dna, known as gene cassettes, by a site-specific recombination mechanism. characterized gene cassettes consist of a target recombination sequence (attc site) usually associated with a single open reading frame coding for an antibiotic resistance determinant. the affiliation of multiresistant integrons (mris), which contain various combinations of antibiotic resistance gene cassettes, with transferable elements underlies the rapid ...	2001	11209061
structures of the o4 and o18 antigens of stenotrophomonas maltophilia: a case of enantiomeric repeating units.	the o-specific side-chain polymers of lipopolysaccharides from the reference strains for stenotrophomonas maltophilia serogroups 04 and o18 are both xylosylated rhamnans. in the 04 polymer, both sugar components are the d isomers, whereas the o18 polymer contains only the l isomers. by means of nmr spectroscopy, methylation analysis and smith degradation, the repeating unit of the 04 polymer was identified as a doubly-branched pentasaccharide of the structure shown below. the o18 polymer is base ...	2001	11217974
biological sensor for sucrose availability: relative sensitivities of various reporter genes.	a set of three sucrose-regulated transcriptional fusions was constructed. fusions p61rytir, p61rylac, and p61ryice contain the scrr sucrose repressor gene and the promoterless gfp, lacz, and inaz reporter genes, respectively, fused to the scry promoter from salmonella enterica serovar typhimurium. cells of erwinia herbicola containing these fusions are induced only in media amended with sucrose, fructose, or sorbose. while a large variation in sucrose-dependent reporter gene activity was observe ...	2001	11229926
salmonella host cell invasion emerged by acquisition of a mosaic of separate genetic elements, including salmonella pathogenicity island 1 (spi1), spi5, and sope2.	salmonella spp. possess a conserved type iii secretion system encoded within the pathogenicity island 1 (spi1; centisome 63), which mediates translocation of effector proteins into the host cell cytosol to trigger responses such as bacterial internalization. several translocated effector proteins are encoded in other regions of the salmonella chromosome. it remains unclear how this complex chromosomal arrangement of genes for the type iii apparatus and the effector proteins emerged and how the d ...	2001	11244077
complete dna sequence and comparative analysis of the 50-kilobase virulence plasmid of salmonella enterica serovar choleraesuis.	the complete nucleotide sequence of pkdsc50, a large virulence plasmid from salmonella enterica serovar choleraesuis strain rf-1, has been determined. we identified 48 of the open reading frames (orfs) encoded by the 49,503-bp molecule. pkdsc50 encodes a known virulence-associated operon, the spv operon, which is composed of genes essential for systemic infection by nontyphoidal salmonella. analysis of the genetic organization of pkdsc50 suggests that the plasmid is composed of several virulence ...	2001	11254626
an inner membrane platform in the type ii secretion machinery of gram-negative bacteria.	the type ii secretion machinery allows most gram-negative bacteria to deliver virulence factors into their surroundings. we report that in erwinia chrysanthemi, gspe (the putative ntpase), gspf, gspl and gspm constitute a complex in the inner membrane that is presumably used as a platform for assembling other parts of the secretion machinery. the gspe-gspf-gspl-gspm complex was demonstrated by two methods: (i) co-immunoprecipitation of gspe-gspf-gspl with antibodies raised against either gspe or ...	2001	11266368
hydrogen peroxide-forming nadh oxidase belonging to the peroxiredoxin oxidoreductase family: existence and physiological role in bacteria.	amphibacillus xylanus and sporolactobacillus inulinus nadh oxidases belonging to the peroxiredoxin oxidoreductase family show extremely high peroxide reductase activity for hydrogen peroxide and alkyl hydroperoxides in the presence of the small disulfide redox protein, ahpc (peroxiredoxin). in order to investigate the distribution of this enzyme system in bacteria, 15 bacterial strains were selected from typical aerobic, facultatively anaerobic, and anaerobic bacteria. ahpc-linked alkyl hydroper ...	2001	11274101
complete dna sequence and analysis of the large virulence plasmid of shigella flexneri.	the complete sequence analysis of the 210-kb shigella flexneri 5a virulence plasmid was determined. shigella spp. cause dysentery and diarrhea by invasion and spread through the colonic mucosa. most of the known shigella virulence determinants are encoded on a large plasmid that is unique to virulent strains of shigella and enteroinvasive escherichia coli; these known genes account for approximately 30 to 35% of the virulence plasmid. in the complete sequence of the virulence plasmid, 286 open r ...	2001	11292750
study of the role of antimicrobial glucosinolate-derived isothiocyanates in resistance of arabidopsis to microbial pathogens.	crude aqueous extracts from arabidopsis leaves were subjected to chromatographic separations, after which the different fractions were monitored for antimicrobial activity using the fungus neurospora crassa as a test organism. two major fractions were obtained that appeared to have the same abundance in leaves from untreated plants versus leaves from plants challenge inoculated with the fungus alternaria brassicicola. one of both major antimicrobial fractions was purified to homogeneity and iden ...	2001	11299350