Publications

biosynthesis of carbapenem antibiotic and prodigiosin pigment in serratia is under quorum sensing control.	serratia sp. atcc 39006 produces the carbapenem antibiotic, carbapen-2-em-3-carboxylic acid and the red pigment, prodigiosin. we have previously reported the characterization of a gene, carr, controlling production of carbapenem in this strain. we now describe further characterization of the carr locus to locate the genes encoding carbapenem biosynthetic and resistance functions. a novel family of diverse proteins showing sequence similarity to the c-terminal domain of carf (required for carbape ...	2000	10844645
a regulatory rna (prrb rna) modulates expression of secondary metabolite genes in pseudomonas fluorescens f113.	the gacs-gaca two-component signal transduction system, which is highly conserved in gram-negative bacteria, is required for the production of exoenzymes and secondary metabolites in pseudomonas spp. screening of a pseudomonas fluorescens f113 gene bank led to the isolation of a previously undefined locus which could restore secondary metabolite production to both gacs and gaca mutants of f113. sequence analysis of this locus demonstrated that it did not contain any obvious pseudomonas protein-c ...	2000	10869066
influence of deletions within domain ii of exotoxin a on its extracellular secretion from pseudomonas aeruginosa.	pseudomonas aeruginosa is a gram-negative bacterium that secretes many proteins into the extracellular medium via the xcp machinery. this pathway, conserved in gram-negative bacteria, is called the type ii pathway. the exoproteins contain information in their amino acid sequence to allow targeting to their secretion machinery. this information may be present within a conformational motif. the nature of this signal has been examined for p. aeruginosa exotoxin a (pe). previous studies failed to id ...	2000	10869085
identification and cell cycle control of a novel pilus system in caulobacter crescentus.	pilus assembly in caulobacter: crescentus occurs during a short period of the cell cycle and pili are only present at the flagellar pole of the swarmer cell. here we report a novel assay to visualize pili by light microscopy that led to the purification of caulobacter: pili and the isolation of a cluster of seven genes, including the major pilin subunit gene pila. this gene cluster encodes a novel group of pilus assembly proteins. we have shown that the pila promoter is activated late in the cel ...	2000	10880436
vibrio fischeri lux genes play an important role in colonization and development of the host light organ.	the bioluminescent bacterium vibrio fischeri and juveniles of the squid euprymna scolopes specifically recognize and respond to one another during the formation of a persistent colonization within the host's nascent light-emitting organ. the resulting fully developed light organ contains brightly luminescing bacteria and has undergone a bacterium-induced program of tissue differentiation, one component of which is a swelling of the epithelial cells that line the symbiont-containing crypts. while ...	2000	10913092
a carboxy-terminal 16-amino-acid region of sigma(38) of escherichia coli is important for transcription under high-salt conditions and sigma activities in vivo.	sigma(38) (or sigma(s), the rpos gene product) is a sigma subunit of rna polymerase in escherichia coli and directs transcription from a number of stationary-phase promoters as well as osmotically inducible promoters. in this study, we analyzed the function of the carboxy-terminal 16-amino-acid region of sigma(38) (residues 315 to 330), which is well conserved among the rpos gene products of enteric bacterial species. truncation of this region was shown to result in the loss of sigma activity in ...	2000	10913098
controlling instability in gacs-gaca regulatory genes during inoculant production of pseudomonas fluorescens biocontrol strains.	secondary metabolism in fluorescent pseudomonads is globally regulated by gacs, which encodes a membrane-bound sensor kinase, and gaca, which encodes a transcriptional response regulator. spontaneous mutation in either gene blocked biosynthesis of the antimicrobial compounds hydrogen cyanide, 2,4-diacetylphloroglucinol, pyoluteorin, and pyrrolnitrin by the model biocontrol strain pseudomonas fluorescens cha0. spontaneous mutants also had altered abilities to utilize several carbon sources and to ...	2000	10919762
a genomic sample sequence of the entomopathogenic bacterium photorhabdus luminescens w14: potential implications for virulence.	photorhabdus luminescens is a pathogenic bacterium that lives in the guts of insect-pathogenic nematodes. after invasion of an insect host by a nematode, bacteria are released from the nematode gut and help kill the insect, in which both the bacteria and the nematodes subsequently replicate. however, the bacterial virulence factors associated with this "symbiosis of pathogens" remain largely obscure. in order to identify genes encoding potential virulence factors, we performed approximately 2,00 ...	2000	10919786
structure and function of pectic enzymes: virulence factors of plant pathogens.	the structure and function of erwinia chrysanthemi pectate lysase c, a plant virulence factor, is reviewed to illustrate one mechanism of pathogenesis at the molecular level. current investigative topics are discussed in this paper.	2000	10922032
acyl-homoserine lactone quorum sensing in gram-negative bacteria: a signaling mechanism involved in associations with higher organisms.	recent advances in studies of bacterial gene expression have brought the realization that cell-to-cell communication and community behavior are critical for successful interactions with higher organisms. species-specific cell-to-cell communication is involved in successful pathogenic or symbiotic interactions of a variety of bacteria with plant and animal hosts. one type of cell-cell signaling is acyl-homoserine lactone quorum sensing in gram-negative bacteria. this type of quorum sensing repres ...	2000	10922036
establishment of introduced antagonistic bacteria in the rhizosphere of transgenic potatoes and their effect on the bacterial community.	in a field release experiment, rifampicin resistant mutants of two antagonistic plant-associated bacteria were used for seed tuber inoculation of transgenic t4 lysozyme expressing potatoes, transgenic control potatoes and non-transgenic parental potatoes. the t4 lysozyme tolerant pseudomonas putida qc14-3-8 was originally isolated from the tuber surface (geocaulosphere) of t4 lysozyme producing plants and showed in vitro antibacterial activity to the bacterial pathogen erwinia carotovora ssp. at ...	2000	10922502
inhibition of fungal and bacterial plant pathogens by synthetic peptides: in vitro growth inhibition, interaction between peptides and inhibition of disease progression.	four synthetic cationic peptides, pep6, pep7, pep11 and pep20, were tested alone and in combinations for their antimicrobial activities against economically important plant pathogenic fungi (phytophthora infestans and alternaria solani) and bacteria (erwinia carotovora subsp. carotovora and e. carotovora subsp. atroseptica). in in vitro studies, p. infestans and a. solani were inhibited by all four peptides, while e. carotovora subsp. carotovora and e. carotovora subsp. atroseptica were inhibite ...	2000	10939256
induced expression of sarcotoxin ia enhanced host resistance against both bacterial and fungal pathogens in transgenic tobacco.	we demonstrate here that induced expression of sarcotoxin ia, a bactericidal peptide from sarcophaga peregrina, enhanced the resistance of transgenic tobacco plants to both bacterial and fungal pathogens. the peptide was produced with a modified pr1a promoter, which is further activated by salicylic acid treatment and necrotic lesion formation by pathogen infection. host resistance to infection of bacteria erwinia carotovora subsp. carotovora and pseudomonas syringae pv. tabaci was shown to be d ...	2000	10939257
bacteria in the leaf ecosystem with emphasis on pseudomonas syringae-a pathogen, ice nucleus, and epiphyte.	the extremely large number of leaves produced by terrestrial and aquatic plants provide habitats for colonization by a diversity of microorganisms. this review focuses on the bacterial component of leaf microbial communities, with emphasis on pseudomonas syringae-a species that participates in leaf ecosystems as a pathogen, ice nucleus, and epiphyte. among the diversity of bacteria that colonize leaves, none has received wider attention than p. syringae, as it gained notoriety for being the firs ...	2000	10974129
identification of brucella abortus oxyr and its role in control of catalase expression.	we report the cloning and sequencing of the brucella abortus oxyr homolog and provide evidence that the transcription product of this gene binds to the b. abortus catalase promoter region. a gene replacement/deletion brucella oxyr mutant exhibits increased sensitivity to prolonged exposure to h(2)o(2) and is unable to adapt to h(2)o(2) in the environment.	2000	10986275
keys to symbiotic harmony.		2000	11004160
new virulence-activated and virulence-repressed genes identified by systematic gene inactivation and generation of transcriptional fusions in bordetella pertussis.	an in silico scan of the partially completed genome sequence of bordetella pertussis and analyses of transcriptional fusions generated with a new integrational vector were used to identify new potential virulence genes. the genes encoding a putative siderophore receptor, adhesins, and an autotransporter protein appeared to be regulated in a manner similar to bordetella virulence genes by the global virulence regulator bvgas. in contrast, the gene encoding a putative intimin-like protein appeared ...	2000	11004193
quorum-sensing signal binding results in dimerization of trar and its release from membranes into the cytoplasm.	promoter binding by trar and luxr, the activators of two bacterial quorum-sensing systems, requires their cognate acyl-homoserine lactone (acyl-hsl) signals, but the role the signal plays in activating these transcription factors is not known. soluble active trar, when purified from cells grown with the acyl-hsl, contained bound signal and was solely in dimer form. however, genetic and cross-linking studies showed that trar is almost exclusively in monomer form in cells grown without signal. add ...	2000	11013223
pseudobactin biogenesis in the plant growth-promoting rhizobacterium pseudomonas strain b10: identification and functional analysis of the l-ornithine n(5)-oxygenase (psba) gene.	pseudobactin(b10), the fluorescent siderophore produced by the rhizobacterium pseudomonas strain b10, contains the hydroxamate ligand d-n(5)-hydroxyornithine (d-n(5)-oh-orn). we cloned the l-orn n(5)-oxygenase (psba) gene from a genomic library of pseudomonas strain b10 and demonstrated that psba is involved in the conversion of l-orn to its n(5)-oh derivative. psba shows significant similarity to microbial omega-amino acid hydroxylases containing flavin adenine dinucleotide and nadp cofactor-bi ...	2000	11029447
an escherichia coli reference collection group b2- and uropathogen-associated polymorphism in the rpos-muts region of the e. coli chromosome.	chromosomal dnas of enterohemorrhagic, uropathogenic, and laboratory attenuated escherichia coli strains differ in the rpos-muts region. many uropathogens lack a deletion and an insertion characteristic of enterohemorrhagic strains. at the same chromosomal position, they harbor a 2.1-kb insertion of unknown origin with a base composition suggestive of horizontal gene transfer. unlike virulence determinants associated with urinary tract infection and/or neonatal meningitis (pap or prs, sfa, kps, ...	2000	11029456
antimicrobial effect of rosemary extracts.	a rosemary extract commercially exploited (oxy'less) as an antioxidant of lipids in foods was dissolved in ethanol (100 mg/ml), and the solution was tested against foodborne microorganisms. for gram-positive bacteria, the mic of the ethanolic solution was 1% for leuconostoc mesenteroides, 0.5% for listeria monocytogenes, 0.5% for staphylococcus aureus, 0.13% for streptococcus mutans, and 0.06% for bacillus cereus. it slowed the growth of penicillium roquefortii and botrytis cinerea. up to 1% of ...	2000	11041135
a potato gene encoding a wrky-like transcription factor is induced in interactions with erwinia carotovora subsp. atroseptica and phytophthora infestans and is coregulated with class i endochitinase expression.	a potato gene encoding a putative wrky protein was isolated from a cdna library enriched by suppression subtractive hybridization for sequences upregulated 1 h postinoculation with erwinia carotovora subsp. atroseptica. the cdna encodes a putative polypeptide of 172 amino acids, containing a single wrky domain with a zinc finger motif and preceded by a potential nuclear localization site. st-wrky1 was strongly upregulated in compatible, but only weakly in incompatible, interactions with phytopht ...	2000	11043470
the pseudomonas aeruginosa lectins pa-il and pa-iil are controlled by quorum sensing and by rpos.	in pseudomonas aeruginosa, many exoproduct virulence determinants are regulated via a hierarchical quorum-sensing cascade involving the transcriptional regulators lasr and rhlr and their cognate activators, n-(3-oxododecanoyl)-l-homoserine lactone (3o-c12-hsl) and n-butanoyl-l-homoserine lactone (c4-hsl). in this paper, we demonstrate that the cytotoxic lectins pa-il and pa-iil are regulated via quorum sensing. using immunoblot analysis, the production of both lectins was found to be directly de ...	2000	11053384
analysis of the role of reca in phenotypic switching of pseudomonas tolaasii.	switching between the pathogenic smooth (1116s) and nonpathogenic rough (1116r) forms of pseudomonas tolaasii occurs due to the reversible duplication of a 661-bp element within the phen locus. disruption of the chromosomal reca locus of 1116s and 1116r produced strains 1116sreca and 1116rreca, respectively, which showed typical loss of uv resistance. switching from the smooth to the rough form was virtually eliminated in the 1116sreca strain, whereas the extent of switching from the rough to th ...	2000	11053404
attachment of escherichia coli o157:h7 to the surfaces and internal structures of apples as detected by confocal scanning laser microscopy.	confocal scanning laser microscopy (cslm) was used to demonstrate the attachment of escherichia coli o157:h7 transformed with a plasmid encoding for green fluorescent protein (gfp) to the surface and within the internal structures of nonwaxed red delicious cv. apples. apples at 2 or 25 degrees c were inoculated with an e. coli o157:h7 cell suspension at 2 or 25 degrees c. the effect of a negative temperature differential (cold inoculum, warm apple), a positive differential (warm inoculum, cold a ...	2000	11055910
identification of ciprofloxacin-resistant campylobacter jejuni by use of a fluorogenic pcr assay.	fluoroquinolones are one class of antimicrobial agents commonly used to treat severe campylobacter jejuni infection. c. jejuni strains resistant to high levels of the fluoroquinolone ciprofloxacin (mic >/=16 microg/ml) have been predominantly characterized with a c-->t transition in codon 86 of gyra. the gyra gene encodes one subunit of dna gyrase, which is a primary target for fluoroquinolone antibiotics. this study establishes a rapid pcr-based taqman method for identifying ciprofloxacin-resis ...	2000	11060054
linear beta-1,3 glucans are elicitors of defense responses in tobacco.	laminarin, a linear beta-1,3 glucan (mean degree of polymerization of 33) was extracted and purified from the brown alga laminaria digitata. its elicitor activity on tobacco (nicotiana tabacum) was compared to that of oligogalacturonides with a mean degree of polymerization of 10. the two oligosaccharides were perceived by suspension-cultured cells as distinct chemical stimuli but triggered a similar and broad spectrum of defense responses. a dose of 200 microg ml(-1) laminarin or oligogalacturo ...	2000	11080280
identification and characterization of yersinia enterocolitica genes induced during systemic infection.	yersinia enterocolitica is one of three pathogenic yersinia species that share a tropism for lymphoid tissues. however, infection of an immunocompromised host is likely to result in a systemic infection, which is often fatal. little is known about the bacterial proteins needed to establish such an infection. the genes that encode these virulence factors are likely to be active only during systemic infection. a library of random cat fusions was used to inoculate balb/c mice. fusions expressed dur ...	2000	11083775
regulation of salmonella enterica serovar typhimurium invasion genes by csra.	penetration of intestinal epithelial cells by salmonella enterica serovar typhimurium requires the expression of invasion genes, found in salmonella pathogenicity island 1 (spi1), that encode components of a type iii secretion apparatus. these genes are controlled in a complex manner by regulators within spi1, including hila and invf, and those outside spi1, such as the two-component regulators phop/phoq and bara/sira. we report here that epithelial cell invasion requires the serovar typhimurium ...	2000	11083797
metabolism of acyl-homoserine lactone quorum-sensing signals by variovorax paradoxus.	acyl-homoserine lactones (acyl-hsls) serve as dedicated cell-to-cell signaling molecules in many species of the class proteobacteria. we have addressed the question of whether these compounds can be degraded biologically. a motile, rod-shaped bacterium was isolated from soil based upon its ability to utilize n-(3-oxohexanoyl)-l-homoserine lactone as the sole source of energy and nitrogen. the bacterium was classified as a strain of variovorax paradoxus. the v. paradoxus isolate was capable of gr ...	2000	11092851
improved barley broiler feed with transgenic malt containing heat-stable (1,3-1,4)-beta-glucanase.	the low nutritional value of barley for poultry is because of the absence of an intestinal enzyme for efficient depolymerization of (1, 3-1,4)-beta-glucan, the major polysaccharide of the endosperm cell walls. this leads to high viscosity in the intestine, limited nutrient uptake, decreased growth rate, and unhygienic sticky droppings adhering to chickens and floors of the production cages. consequently, the 7.5 billion broiler chickens produced annually in the united states are primarily raised ...	2000	11106393
bacterial quorum sensing in pathogenic relationships.		2000	10948095
bacterial growth stimulation with exogenous siderophore and synthetic n-acyl homoserine lactone autoinducers under iron-limited and low-nutrient conditions.	the growth of marine bacteria under iron-limited conditions was investigated. neither siderophore production nor bacterial growth was detected for pelagiobacter sp. strain v0110 when fe(iii) was present in the culture medium at a concentration of <1.0 microm. however, the growth of v0110 was strongly stimulated by the presence of trace amounts of exogenous siderophore from an alpha proteobacterium, v0902, and 1 nm n-acyl-octanoylhomoserine lactone (c(8)-hsl), which is known as a quorum-sensing c ...	2000	10877770
how novel methods can help discover more information about foodborne pathogens.	considerable emphasis is being placed on quantitative risk assessment modelling as a basis for regulation of trade in food products. however, for models to be accurate, information about the behaviour of potential pathogens in foods needs to be available. the question is how to obtain this knowledge in a simple and cost effective way. one technique that has great potential is the use of reporter bacteria which have been genetically modified to express a phenotype that can be easily monitored, su ...	2000	18159282
the drosophila caspase dredd is required to resist gram-negative bacterial infection.	the drosophila innate immune system discriminates between pathogens and responds by inducing the expression of specific antimicrobial peptide-encoding genes through distinct signaling cascades. fungal infection activates nf-kappab-like transcription factors via the toll pathway, which also regulates innate immune responses in mammals. the pathways that mediate antibacterial defenses, however, are less defined. we have isolated loss-of-function mutations in the caspase encoding gene dredd, which ...	2000	11269502
mutations in the drosophila dtak1 gene reveal a conserved function for mapkkks in the control of rel/nf-kappab-dependent innate immune responses.	in mammals, tak1, a mapkkk kinase, is implicated in multiple signaling processes, including the regulation of nf-kappab activity via the il1-r/tlr pathways. tak1 function has largely been studied in cultured cells, and its in vivo function is not fully understood. we have isolated null mutations in the drosophila dtak1 gene that encodes dtak1, a homolog of tak1. dtak1 mutant flies are viable and fertile, but they do not produce antibacterial peptides and are highly susceptible to gram-negative b ...	2001	11485985
type ii secretion and pathogenesis.		2001	11349009
polarity in action: asymmetric protein localization in bacteria.		2001	11344132
novel receptor-like protein kinases induced by erwinia carotovora and short oligogalacturonides in potato.	summary identification of potato genes responsive to cell wall-degrading enzymes of erwinia carotovora resulted in the isolation of cdna clones for four related receptor-like protein kinases. one of the putative serine-threonine protein kinases might have arisen through alternative splicing. these potato receptor-like kinases (prk1-4) were highly equivalent (91-99%), most likely constituting a family of related receptors. all prks and four other plant rlks share in their extracellular domain a c ...	2001	20573023
agricultural microbes genome 2: first glimpses into the genomes of plant-associated microbes.		2001	11251088
pantoea agglomerans strain eh318 produces two antibiotics that inhibit erwinia amylovora in vitro.	pantoea agglomerans (synonym: erwinia herbicola) strain eh318 produces through antibiosis a complex zone of inhibited growth in an overlay seeded with erwinia amylovora, the causal agent of fire blight. this zone is caused by two antibiotics, named pantocin a and b. using a genomic library of eh318, two cosmids, pcpp702 and pcpp704, were identified that conferred on escherichia coli the ability to inhibit growth of e. amylovora. the two cosmids conferred different antibiotic activities on e. col ...	2001	11133457
disulfide bond in pseudomonas aeruginosa lipase stabilizes the structure but is not required for interaction with its foldase.	pseudomonas aeruginosa secretes a 29-kda lipase which is dependent for folding on the presence of the lipase-specific foldase lif. the lipase contains two cysteine residues which form an intramolecular disulfide bond. variant lipases with either one or both cysteines replaced by serines showed severely reduced levels of extracellular lipase activity, indicating the importance of the disulfide bond for secretion of lipase through the outer membrane. wild-type and variant lipase genes fused to the ...	2001	11133953
gfp-based n-acyl homoserine-lactone sensor systems for detection of bacterial communication.	in order to perform single-cell analysis and online studies of n-acyl homoserine lactone (ahl)-mediated communication among bacteria, components of the vibrio fischeri quorum sensor encoded by luxr-p(luxi) have been fused to modified versions of gfpmut3* genes encoding unstable green fluorescent proteins. bacterial strains harboring this green fluorescent sensor detected a broad spectrum of ahl molecules and were capable of sensing the presence of 5 nm n-3-oxohexanoyl-l-homoserine lactone in the ...	2001	11157219
analysis of the type iv fimbrial-subunit gene fima of xanthomonas hyacinthi: application in pcr-mediated detection of yellow disease in hyacinths.	a sensitive and specific detection method was developed for xanthomonas hyacinthi; this method was based on amplification of a subsequence of the type iv fimbrial-subunit gene fima from strain s148. the fima gene was amplified by pcr with degenerate dna primers designed by using the n-terminal and c-terminal amino acid sequences of trypsin fragments of fima. the nucleotide sequence of fima was determined and compared with the nucleotide sequences coding for the fimbrial subunits in other type iv ...	2001	11157222
disulfide bond formation in secreton component pulk provides a possible explanation for the role of dsba in pullulanase secretion.	when expressed in escherichia coli, the 15 klebsiella oxytoca pul genes that encode the so-called pul secreton or type ii secretion machinery promote pullulanase secretion and the assembly of one of the secreton components, pulg, into pili. besides these pul genes, efficient pullulanase secretion also requires the host dsba gene, encoding a periplasmic disulfide oxidoreductase, independently of disulfide bond formation in pullulanase itself. two secreton components, the secretin pilot protein pu ...	2001	11157944
subset of hybrid eukaryotic proteins is exported by the type i secretion system of erwinia chrysanthemi.	erwinia chrysanthemi exports degradative enzymes by using a type i protein secretion system. the proteases secreted by this system lack an n-terminal signal peptide but contain a c-terminal secretion signal. to explore the substrate specificity of this system, we have expressed the e. chrysanthemi transporter system (prtdef genes) in escherichia coli and tested the ability of this abc transporter to export hybrid proteins carrying c-terminal fragments of e. chrysanthemi protease b. the c terminu ...	2001	11157948
potential symbiosis-specific genes uncovered by sequencing a 410-kilobase dna region of the bradyrhizobium japonicum chromosome.	the physical and genetic map of the bradyrhizobium japonicum chromosome revealed that nitrogen fixation and nodulation genes are clustered. because of the complex interactions between the bacterium and the plant, we expected this chromosomal sector to contain additional genes that are involved in the maintenance of an efficient symbiosis. therefore, we determined the nucleotide sequence of a 410-kb region. the overall g+c nucleotide content was 59.1%. using a minimum gene length of 150 nucleotid ...	2001	11157954
the arabidopsis isr1 locus controlling rhizobacteria-mediated induced systemic resistance is involved in ethylene signaling.	in arabidopsis, the rhizobacterial strain pseudomonas fluorescens wcs417r triggers an induced systemic resistance (isr) response that is effective against different types of pathogens. the isr signaling pathway functions independent of salicylic acid, but requires responsiveness to jasmonate (ja) and ethylene. using the genetic variability of isr inducibility between arabidopsis accessions, we recently identified a locus (isr1) on chromosome iii that is involved in isr signaling. accessions rld ...	2001	11161023
jasmonate-dependent induction of indole glucosinolates in arabidopsis by culture filtrates of the nonspecific pathogen erwinia carotovora.	elicitors from the plant pathogen erwinia carotovora trigger coordinate induction of the tryptophan (trp) biosynthesis pathway and trp oxidizing genes in arabidopsis. to elucidate the biological role of such pathogen-induced activation we characterized the production of secondary defense metabolites such as camalexin and indole glucosinolates derived from precursors of this pathway. elicitor induction was followed by a specific increase in 3-indolylmethylglucosinolate (igs) content, but only a b ...	2001	11402212
diversity of polyamine patterns in soft rot pathogens and other plant-associated members of the enterobacteriaceae.	polyamine profiles of 91 pectolytic and other plant-associated strains from 30 taxa of the enterobacteriaceae were obtained by gradient high performance liquid chromatography (hplc). pectobacterium carotovorum, basonym erwinia carotovora, contained a high amount of putrescine and less diaminopropane. diaminopropane was absent in pectobacterium chrysanthemi, basonym e. chrysanthemi, whereas cadaverine was present in addition to the major compound putrescine. this chemotaxonomic difference reflect ...	2001	11403399
indole can act as an extracellular signal in escherichia coli.	previous work has shown that lacz fusions to the cysk, astd, tnab, and gabt genes in escherichia coli are activated by self-produced extracellular signals. using a combination of ethyl acetate extraction, reversed-phase c(18) chromatography, and thin-layer chromatography, we have purified an extracellular activating signal from e. coli supernatants. mass spectrometry revealed a molecule with an m/z peak of 117, consistent with indole. nuclear magnetic resonance analysis of the purified e. coli f ...	2001	11418561
exo-arabinanase of penicillium chrysogenum able to release arabinobiose from alpha-1,5-l-arabinan.	an exo-arabinanase, designated abnx, was purified from a culture filtrate of penicillium chrysogenum 31b by ammonium sulfate precipitation, anion-exchange chromatography, and hydrophobic chromatography. abnx had an apparent molecular mass of 47 kda. the enzyme released only arabinobiose from the nonreducing terminus of alpha-1,5-l-arabinan and showed no activity towards p-nitrophenyl-alpha-l-arabinofuranoside and alpha-1,5-l-arabinofuranobiose. abnx is the first enzyme with this mode of action.	2001	11425761
novel topology of bfpe, a cytoplasmic membrane protein required for type iv fimbrial biogenesis in enteropathogenic escherichia coli.	enteropathogenic escherichia coli (epec) produces the bundle-forming pilus (bfp), a type iv fimbria that has been implicated in virulence, autoaggregation, and localized adherence to epithelial cells. the bfpe gene is one of a cluster of bfp genes previously shown to encode functions that direct bfp biosynthesis. here, we show that an epec strain carrying a nonpolar mutation in bfpe fails to autoaggregate, adhere to hep-2 cells, or form bfp, thereby demonstrating that bfpe is required for bfp bi ...	2001	11443077
nkbor, a mini-tn10-based transposon for random insertion in the chromosome of gram-negative bacteria and the rapid recovery of sequences flanking the insertion sites in escherichia coli.	we have constructed an r6k-based suicide vector that permits the random insertion of a mini-transposon named nkbor into the chromosome of gram-negative bacteria and the subsequent rapid cloning of sequences flanking the insertion site in escherichia coli. this mini-transposon contains a conditional r6k plasmid origin of replication, a kanamycin resistance gene and unique restriction sites between the is10 inverted repeats. nkbor can be propagated by replication in an e. coli strain containing th ...	2001	11446516
quenching quorum-sensing-dependent bacterial infection by an n-acyl homoserine lactonase.	bacterial cells sense their population density through a sophisticated cell-cell communication system and trigger expression of particular genes when the density reaches a threshold. this type of gene regulation, which controls diverse biological functions including virulence, is known as quorum sensing. quorum-sensing signals, such as acyl-homoserine lactones (ahls), are the essential components of the communication system. ahls regulate virulence gene expression in a range of plant and animal ...	2001	11459062
carbon limitation induces sigma(s)-dependent gene expression in pseudomonas fluorescens in soil.	recent studies employing reporter gene technology indicate that the availabilities of the major nutrients nitrogen, phosphate, and iron to pseudomonas are not severely limited in bulk soil. indirect evidence has pointed to carbon limitation as a severe nutritional stress in this environment. we show that a plasmid (pgm115)-borne transcriptional fusion between the sigma(s)-dependent escherichia coli promoter p(fic) and lacz functions as a reliable reporter for carbon availability in pseudomonas f ...	2001	11472905
assessment of the genetic diversity among strains of xanthomonas cynarae by randomly amplified polymorphic dna analysis and development of specific characterized amplified regions for the rapid identification of x. cynarae.	the randomly amplified polymorphic dna (rapd) method was used to investigate the genetic diversity in xanthomonas cynarae, which causes bacterial bract spot disease of artichoke. this rapd analysis was also intended to identify molecular markers characteristic of this species, in order to develop pcr-based markers which can be used to detect this pathogenic bacterium in artichoke fields. among the 340 rapd primers tested, 40 were selected on their ability to produce reproducible and reliable fin ...	2001	11472907
haemodynamic effects of the bacterial quorum sensing signal molecule, n-(3-oxododecanoyl)-l-homoserine lactone, in conscious, normal and endotoxaemic rats.	n-acylhomoserine lactones (ahls) are small, diffusible signalling molecules, employed by gram-negative bacteria to coordinate gene expression with cell population density. recent in vitro findings indicate that ahls may function as virulence determinants per se, through modification of cytokine production by eukaryotic cells, and by stimulating the relaxation of blood vessels. in the present study, we assessed the influence of ahls on cardiovascular function in conscious rats, and draw attention ...	2001	11487515
global regulators expa (gaca) and kdgr modulate extracellular enzyme gene expression through the rsma-rsmb system in erwinia carotovora subsp. carotovora.	the production of the main virulence determinants, the extracellular plant cell wall-degrading enzymes, and hence virulence of erwinia carotovora subsp. carotovora is controlled by a complex regulatory network. one of the global regulators, the response regulator expa, a gaca homolog, is required for transcriptional activation of the extracellular enzyme genes of this soft-rot pathogen. to elucidate the mechanism of expa control as well as interactions with other regulatory systems, we isolated ...	2001	11497464
type iii secretion contributes to the pathogenesis of the soft-rot pathogen erwinia carotovora: partial characterization of the hrp gene cluster.	the virulence of soft-rot erwinia species is dependent mainly upon secreted enzymes such as pectinases, pectin lyases, and proteases that cause maceration of plant tissue. some soft-rot erwinia spp. also harbor genes homologous to the hypersensitive reaction and pathogenesis (hrp) gene cluster, encoding components of the type iii secretion system. the hrp genes are essential virulence determinants for numerous nonmacerating gram-negative plant pathogens but their role in the virulence of soft-ro ...	2001	11497468
analysis of native microflora and selection of strains antagonistic to human pathogens on fresh produce.	the native microflora of three types of produce (green bell peppers, romaine lettuce, and prepeeled baby carrots) and two types of sprouting seeds (alfalfa and clover) were investigated. aerobic plate count (apc) for each produce or seed type as determined on pseudomonas agar f (paf) with incubation at 28 degrees c was in the range of 4 to 7 log cfu per g of tissue or seed. there was no significant difference (p > or = 0.05) in apc when the determinations were made with three agar media includin ...	2001	11510644
dna microarray-based identification of genes controlled by autoinducer 2-stimulated quorum sensing in escherichia coli.	bacterial cell-to-cell communication facilitates coordinated expression of specific genes in a growth rate-ii and cell density-dependent manner, a process known as quorum sensing. while the discovery of a diffusible escherichia coli signaling pheromone, termed autoinducer 2 (ai-2), has been made along with several quorum sensing genes, the overall number and coordination of genes controlled by quorum sensing through the ai-2 signal has not been studied systematically. we investigated global chan ...	2001	11514505
enhanced disease resistance conferred by expression of an antimicrobial magainin analog in transgenic tobacco.	magainins are a group of short peptides originally isolated from frog skin and thought to function as a natural defense mechanism against infection due to their antimicrobial properties. the engineered magainin analog peptide myp30 was found to inhibit spore germination of the oomycete, peronospora tabacina (adam) in vitro, and the growth of a bacterial pathogen erwinia carotovora subsp. carotovora (jones). transgenic tobacco (nicotiana tabacum l.) plants expressing myp30 were evaluated for resi ...	2001	11525522
control of bacterial motility by environmental factors in polarly flagellated and peritrichous bacteria isolated from lake baikal.	despite numerous studies on bacterial motility, little is known about the regulation of this process by environmental factors in natural isolates. in this study we investigated the control of bacterial motility in response to environmental parameters in two strains isolated from the natural habitat of lake baikal. morphological characterization, carbon source utilization, fermentation analysis, and sequence comparison of 16s rrna genes showed that these strains belong to two distinct genera, i.e ...	2001	11525977
cosecretion of chaperones and low-molecular-size medium additives increases the yield of recombinant disulfide-bridged proteins.	attempts were made to engineer the periplasm of escherichia coli to an expression compartment of heterologous proteins in their native conformation. as a first approach the low-molecular-size additive l-arginine and the redox compound glutathione (gsh) were added to the culture medium. addition of 0.4 m l-arginine and 5 mm reduced gsh increased the yield of a native tissue-type plasminogen activator variant (rpa), consisting of the kringle-2 and the protease domain, and a single-chain antibody f ...	2001	11525996
rapid identification and differentiation of the soft rot erwinias by 16s-23s intergenic transcribed spacer-pcr and restriction fragment length polymorphism analyses.	current identification methods for the soft rot erwinias are both imprecise and time-consuming. we have used the 16s-23s rrna intergenic transcribed spacer (its) to aid in their identification. analysis by its-pcr and its-restriction fragment length polymorphism was found to be a simple, precise, and rapid method compared to current molecular and phenotypic techniques. the its was amplified from erwinia and other genera using universal pcr primers. after pcr, the banding patterns generated allow ...	2001	11526007
gly gene cloning and expression and purification of glycinecin a, a bacteriocin produced by xanthomonas campestris pv. glycines 8ra.	glycinecin a, a bacteriocin produced by xanthomonas campestris pv. glycines, inhibits the growth of x. campestris pv. vesicatoria. we have cloned and expressed the genes encoding glycinecin a in escherichia coli. recombinant glycinecin a was purified from cell extracts by ammonium sulfate precipitation followed by chromatography on q-sepharose, mono q (ion exchange), and size exclusion columns. purified glycinecin a is composed of two polypeptides, is active over a wide ph range (6 to 9), and is ...	2001	11526012
detection of methanotroph diversity on roots of submerged rice plants by molecular retrieval of pmoa, mmox, mxaf, and 16s rrna and ribosomal dna, including pmoa-based terminal restriction fragment length polymorphism profiling.	the diversity of methanotrophic bacteria associated with roots of submerged rice plants was assessed using cultivation-independent techniques. the research focused mainly on the retrieval of pmoa, which encodes the alpha subunit of the particulate methane monooxygenase. a novel methanotroph-specific community-profiling method was established using the terminal restriction fragment length polymorphism (t-rflp) technique. the t-rflp profiles clearly revealed a more complex root-associated methanot ...	2001	11526021
the emerging periplasm-localized subclass of aroq chorismate mutases, exemplified by those from salmonella typhimurium and pseudomonas aeruginosa.	chorismate mutases of the aroq homology class are widespread in the bacteria and the archaea. many of these exist as domains that are fused with other aromatic-pathway catalytic domains. among the monofunctional aroq proteins, that from erwinia herbicola was previously shown to have a cleavable signal peptide and located in the periplasmic compartment. whether or not this might be unique to e. herbicola was unknown.	2001	11532214
sdia of salmonella enterica is a luxr homolog that detects mixed microbial communities.	proteins of the luxr family detect the presence of n-acylhomoserine lactones (ahls) and regulate transcription accordingly. when ahls are synthesized by the same species that detects them, the system allows a bacterium to measure the population density of its own species, a phenomenon known as quorum sensing. the sdia genes of escherichia coli and salmonella enterica serovar typhimurium are predicted to encode luxr homologs. however, these species do not appear to synthesize ahls or any other mo ...	2001	11544237
transgenic plants producing the bacterial pheromone n-acyl-homoserine lactone exhibit enhanced resistance to the bacterial phytopathogen erwinia carotovora.	bacterial pheromones, mainly different homoserine lactones, are central to a number of bacterial signaling processes, including those involved in plant pathogenicity. we previously demonstrated that n-oxoacyl-homoserine lactone (ohl) is essential for quorum sensing in the soft-rot phytopathogen erwinia carotovora. in this pathogen, ohl controls the coordinate activation of genes encoding the main virulence determinants, extracellular plant cell wall degrading enzymes (pcwdes), in a cell density- ...	2001	11551068
salicylic acid and ethylene pathways are differentially activated in melon cotyledons by active or heat-denatured cellulase from trichoderma longibrachiatum.	infiltration of cellulase (ec 3.2.1.4) from trichoderma longibrachiatum into melon (cucumis melo) cotyledons induced several key defense mechanisms and hypersensitive reaction-like symptoms. an oxidative burst was observed 3 hours after treatment and was followed by activation of ethylene and salicylic acid (sa) signaling pathways leading to marked induction of peroxidase and chitinase activities. the treatment of cotyledons by heat-denatured cellulase also led to some induction of peroxidase an ...	2001	11553761
a conserved genetic module that encodes the major virion components in both the coliphage t4 and the marine cyanophage s-pm2.	sequence analysis of a 10-kb region of the genome of the marine cyanomyovirus s-pm2 reveals a homology to coliphage t4 that extends as a contiguous block from gene (g)18 to g23. the order of the s-pm2 genes in this region is similar to that of t4, but there are insertions and deletions of small orfs of unknown function. in t4, g18 codes for the tail sheath, g19, the tail tube, g20, the head portal protein, g21, the prohead core protein, g22, a scaffolding protein, and g23, the major capsid prote ...	2001	11553768
rpos-dependent transcriptional control of spre: regulatory feedback loop.	the stationary-phase response exhibited by escherichia coli upon nutrient starvation is mainly induced by a decrease of the clpxp-dependent degradation of the alternate primary sigma factor rpos. although it is known that the specific regulation of this proteolysis is exercised by the orphan response regulator spre, it remains unclear how spre's activity is regulated in vivo. previous studies have demonstrated that the cellular content of spre itself is paradoxically increased in stationary-phas ...	2001	11566997
regulatory interactions of csr components: the rna binding protein csra activates csrb transcription in escherichia coli.	the global regulator csra (carbon storage regulator) of escherichia coli is a small rna binding protein that represses various metabolic pathways and processes that are induced in the stationary phase of growth, while it activates certain exponential phase functions. both repression and activation by csra involve posttranscriptional mechanisms, in which csra binding to mrna leads to decreased or increased transcript stability, respectively. csra also binds to a small untranslated rna, csrb, form ...	2001	11567002
bulk and rhizosphere soil bacterial communities studied by denaturing gradient gel electrophoresis: plant-dependent enrichment and seasonal shifts revealed.	the bacterial rhizosphere communities of three host plants of the pathogenic fungus verticillium dahliae, field-grown strawberry (fragaria ananassa duch.), oilseed rape (brassica napus l.), and potato (solanum tuberosum l.), were analyzed. we aimed to determine the degree to which the rhizosphere effect is plant dependent and whether this effect would be increased by growing the same crops in two consecutive years. rhizosphere or soil samples were taken five times over the vegetation periods. to ...	2001	11571180
survival of salmonellae on and in tomato plants from the time of inoculation at flowering and early stages of fruit development through fruit ripening.	the fate of salmonellae applied to tomato plants was investigated. five salmonella serotypes were used to inoculate tomato plants before and after fruits set, either by injecting stems with inoculum or brushing flowers with it. ripe tomato fruits were subjected to microbiological analysis. peptone wash water, homogenates of stem scar tissues, and homogenates of fruit pulp were serially diluted and plated on bismuth sulfite agar before and after enrichment. presumptive salmonella colonies were co ...	2001	11571182
dna inversion in the tail fiber gene alters the host range specificity of carotovoricin er, a phage-tail-like bacteriocin of phytopathogenic erwinia carotovora subsp. carotovora er.	carotovoricin er is a phage-tail-like bacteriocin produced by erwinia carotovora subsp. carotovora strain er, a causative agent for soft rot disease in plants. here we studied binding and killing spectra of carotovoricin er preparations for various strains of the bacterium (strains 645ar, ec-2, n786, and p7) and found that the preparations contain two types of carotovoricin er with different host specificities; carotovoricin era possessing a tail fiber protein of 68 kda killed strains 645ar and ...	2001	11591670
isolation and characterisation of the major outer membrane protein of erwinia carotovora.	the purified major outer membrane protein (37275 da) from the psychrotrophic phytopathogen erwinia carotovora mfcl0 was structurally characterised by maldi-tof mass spectrometry, n-terminal microsequencing and dna sequence determinations, and secondary structure prediction analyses. the deduced amino acid sequence showed 76% and 72% of similarities with the serratia marcescens and escherichia coli ompa proteins respectively. dendrogram analysis allowed to point out that e. carotovora is close to ...	2001	11597348
the global posttranscriptional regulator rsma modulates production of virulence determinants and n-acylhomoserine lactones in pseudomonas aeruginosa.	posttranscriptional control is known to contribute to the regulation of secondary metabolism and virulence determinants in certain gram-negative bacteria. here we report the isolation of a pseudomonas aeruginosa gene which encodes a global translational regulatory protein, rsma (regulator of secondary metabolites). overexpression of rsma resulted in a substantial reduction in the levels of extracellular products, including protease, elastase, and staphylolytic (lasa protease) activity as well as ...	2001	11673439
colicin a immunity protein interacts with the hydrophobic helical hairpin of the colicin a channel domain in the escherichia coli inner membrane.	the colicin a pore-forming domain (pfcola) was fused to a bacterial signal peptide (sp-pfcola). this was inserted into the escherichia coli inner membrane in functional form and could be coimmunoprecipitated with epitope-tagged immunity protein (epcai). we constructed a series of fusion proteins in which various numbers of sp-pfcola alpha-helices were fused to alkaline phosphatase (ap). we showed that a fusion protein made up of the hydrophobic alpha-helices 8 and 9 of sp-pfcola fused to ap was ...	2001	11673448
prevention and management of antineoplastic-induced hypersensitivity reactions.	acute hypersensitivity reactions (hsrs) are an unpredictable and potentially catastrophic complication of treatment with chemotherapeutic agents. reactions may affect any organ system in the body and range widely in severity from mild pruritus to systemic anaphylaxis. certain classes of chemotherapeutic agents, such as the taxanes, platinum compounds, asparaginases, and epipodophyllotoxins are commonly associated with hsrs. the clinical characteristics of these high risk agents with respect to h ...	2001	11676304
structural requirements of endopolygalacturonase for the interaction with pgip (polygalacturonase-inhibiting protein).	to invade a plant tissue, phytopathogenic fungi produce several cell wall-degrading enzymes; among them, endopolygalacturonase (pg) catalyzes the fragmentation and solubilization of homogalacturonan. polygalacturonase-inhibiting proteins (pgips), found in the cell wall of many plants, counteract fungal pgs by forming specific complexes with them. we report the crystal structure at 1.73 a resolution of pg from the phytopathogenic fungus fusarium moniliforme (fmpg). the structure of fmpg was usefu ...	2001	11687632
the global regulators gaca and sigma(s) form part of a cascade that controls alginate production in azotobacter vinelandii.	transcription of the azotobacter vinelandii algd gene, which encodes gdp-mannose dehydrogenase (the rate-limiting enzyme of alginate synthesis), starts from three sites: p1, p2, and p3. the sensor kinase gacs, a member of the two-component regulatory system, is required for transcription of algd from its three sites during the stationary phase. here we show that algd is expressed constitutively throughout the growth cycle from the p2 and p3 sites and that transcription from p1 started at the tra ...	2001	11698366
organization of genes controlling disease resistance in the potato genome.	nineteen single dominant genes (r genes) for resistance to viruses, nematodes, and fungi have been positioned on the molecular map of potato using dna markers. fourteen of those genes are located in five "hotspots" for resistance in the potato genome. quantitative trait loci (qtl) for resistance to late blight caused by the oomycete phytophthora infestans, to tuber rot caused by the bacterium erwinia carotovora ssp. atroseptica, and to root cyst nematodes have been identified on all 12 potato ch ...	2001	11701860
expression of an antimicrobial peptide via the chloroplast genome to control phytopathogenic bacteria and fungi.	the antimicrobial peptide msi-99, an analog of magainin 2, was expressed via the chloroplast genome to obtain high levels of expression in transgenic tobacco (nicotiana tabacum var. petit havana) plants. polymerase chain reaction products and southern blots confirmed integration of msi-99 into the chloroplast genome and achievement of homoplasmy, whereas northern blots confirmed transcription. contrary to previous predictions, accumulation of msi-99 in transgenic chloroplasts did not affect norm ...	2001	11706168
proteins induced during adaptation of acetobacter aceti to high acetate concentrations.	as a typical product of microbial metabolism, the weak acid acetate is well known for its cytotoxic effects. in contrast to most other microbes, the so-called acetic acid bacteria can acquire significant resistance to high acetate concentrations when properly adapted to such hostile conditions. to characterize the molecular events that are associated with this adaptation, we analyzed global protein expression levels during adaptation of acetobacter aceti by two-dimensional gel electrophoresis. a ...	2001	11722895
characterization of enterocoliticin, a phage tail-like bacteriocin, and its effect on pathogenic yersinia enterocolitica strains.	yersinia enterocolitica 29930 (biogroup 1a; serogroup o:7,8) produces a bacteriocin, designated enterocoliticin, that shows inhibitory activity against enteropathogenic strains of y. enterocolitica belonging to serogroups o:3, o:5,27 and o:9. enterocoliticin was purified, and electron micrographs of enterocoliticin preparations revealed the presence of phage tail-like particles. the particles did not contain nucleic acids and showed contraction upon contact with susceptible bacteria. enterocolit ...	2001	11722917
visualization of n-acylhomoserine lactone-mediated cell-cell communication between bacteria colonizing the tomato rhizosphere.	given that a large proportion of the bacteria colonizing the roots of plants is capable of producing n-acyl-l-homoserine lactone (ahl) molecules, it appears likely that these bacterial pheromones may serve as signals for communication between cells of different species. in this study, we have developed and characterized novel gfp-based monitor strains that allow in situ visualization of ahl-mediated communication between individual cells in the plant rhizosphere. for this purpose, three gfp-base ...	2001	11722933
overexpresssion of a legionella pneumophila homologue of the e. coli regulator csra affects cell size, flagellation, and pigmentation.	legionella pneumophila is an inhabitant of the aquatic environment and the causative agent of a bacterial pneumonia. we identified the presence of an l. pneumophila homologue of csra of e. coli and rsma of erwinia carotovora, genes which regulate gene expression by destabilising mrna and which have been shown to relate to environmental fitness and pathogenicity. the legionella csra was able to complement a csra-negative mutant of e. coli. overproduction of csra in l. pneumophila lead to a reduct ...	2001	11727819
halogenated furanones from the red alga, delisea pulchra, inhibit carbapenem antibiotic synthesis and exoenzyme virulence factor production in the phytopathogen erwinia carotovora.	the plant pathogen erwinia carotovora regulates expression of virulence factors and antibiotic production via an n-3-oxohexanoyl-l-homoserine lactone (3-oxo-c6-hsl) dependent quorum sensing mechanism. the marine alga delisea pulchra produces halogenated furanones known to antagonise 3-oxo-c6-hsl activity. we have tested the effects of a halogenated furanone on the production of carbapenem, cellulase and protease in e. carotovora. despite differences in the regulatory mechanisms controlling carba ...	2001	11728727
optimization of fermentation reaction conditions for preparation of pate enzyme by erwinia carotovora ifo3830 by tfccrd method.	the fermentation conditions for preparation of polygalacturonic acid transeliminase (pate) enzyme by erwinia carotovora ifo3830 were optimized for seed ratio, vibration rate, and temperature by the tfccrd method. the results indicated that the optimum fermentation conditions for e. carotovora ifo 3830 were that seed ratio, vibration rate, and temperature were 5% v/v, 113 min(-1), and 29 degrees c, respectively.	2001	11735434
enteric bacteria counteract lipopolysaccharide induction of antimicrobial peptide genes.	the humoral immunity of drosophila involves the production of antimicrobial peptides, which are induced by evolutionary conserved microbial molecules, like lps. by using drosophila mbn-2 cells, we found that live bacteria, including e. coli, salmonella typhimurium, erwinia carotovora, and pseudomonas aeruginosa, prevented lps from inducing antimicrobial peptide genes, while micrococcus luteus and streptococcus equi did not. the inhibitory effect was seen at bacterial levels from 20 per mbn-2 cel ...	2001	11739510
[isolation and preliminary characterization of cryptic plasmids from erwinia carotovora].	of the fifty-two erwinia carotovora strains studied, sixteen were found to contain extrachromosomal dna (plasmids) from 2.5 to 129 kbp in size. some e. carotovora strains bore two to five different plasmids. experiments showed that the cryptic plasmids of erwinia are not responsible for their resistance to antibiotics and are not involved in the synthesis of macromolecular colicin-like carotovoricins. at the same time, one of the e. carotovora strains, 13a, augmented the production of carotovori ...	2001	11785137
effect of high oxygen modified atmosphere packaging on microbial growth and sensorial qualities of fresh-cut produce.	the application of high oxygen atmospheres (hoa) (i.e. > 70% o2) for packaging ready-to-eat vegetables was evaluated as an alternative technique for low o2 equilibrium modified atmosphere (ema) packaging (3% o2-5% co2-balance n2) for respiring products. comparative experiments between both techniques were performed in-vitro and in-vivo. typical spoilage causing microorganisms (pseudomonas fluorescens, candida lambica), the moulds botrytis cinerea, aspergillus flavus and the opportunistic psychro ...	2001	11789938
the pleiotropic two-component regulatory system phop-phoq.		2001	11222580
molecular characterization of global regulatory rna species that control pathogenicity factors in erwinia amylovora and erwinia herbicola pv. gypsophilae.	rsmb(ecc) specifies a nontranslatable rna regulator that controls exoprotein production and pathogenicity in soft rot-causing erwinia carotovora subsp. carotovora. this effect of rsmb(ecc) rna is mediated mostly by neutralizing the function of rsma(ecc), an rna-binding protein of e. carotovora subsp. carotovora, which acts as a global negative regulator. to determine the occurrence of functional homologs of rsmb(ecc) in non-soft-rot-causing erwinia species, we cloned the rsmb genes of e. amylovo ...	2001	11222584
phylogeny of genes for secretion ntpases: identification of the widespread tada subfamily and development of a diagnostic key for gene classification.	macromolecular transport systems in bacteria currently are classified by function and sequence comparisons into five basic types. in this classification system, type ii and type iv secretion systems both possess members of a superfamily of genes for putative ntp hydrolase (ntpase) proteins that are strikingly similar in structure, function, and sequence. these include virb11, trbb, trag, gspe, pilb, pilt, and comg1. the predicted protein product of tada, a recently discovered gene required for t ...	2001	11226268
acyl-homoserine lactone production is more common among plant-associated pseudomonas spp. than among soilborne pseudomonas spp.	a total of 137 soilborne and plant-associated bacterial strains belonging to different pseudomonas species were tested for their ability to synthesize n-acyl-homoserine lactones (nahl). fifty-four strains synthesized nahl. interestingly, nahl production appears to be more common among plant-associated than among soilborne pseudomonas spp. indeed, 40% of the analyzed pseudomonas syringae strains produced nahl which were identified most often as the short-chain nahl, n-hexanoyl-l-homoserine lacton ...	2001	11229911
the rssb response regulator directly targets sigma(s) for degradation by clpxp.	the sigma(s) subunit of escherichia coli rna polymerase regulates the expression of stationary phase and stress response genes. control over sigma(s) activity is exercised in part by regulated degradation of sigma(s). in vivo, degradation requires the clpxp protease together with rssb, a protein homologous to response regulator proteins. using purified components, we reconstructed the degradation of sigma(s) in vitro and demonstrate a direct role for rssb in delivering sigma(s) to clpxp. rssb gr ...	2001	11238382