| molecular characterization of a brucella species large dna fragment deleted in brucella abortus strains: evidence for a locus involved in the synthesis of a polysaccharide. | a brucella melitensis 16m dna fragment of 17,119 bp, which contains a large region deleted in b. abortus strains and dna flanking one side of the deletion, has been characterized. in addition to the previously identified omp31 gene, 14 hypothetical genes have been identified in the b. melitensis fragment, most of them showing homology to genes involved in the synthesis of a polysaccharide. considering that 10 of the 15 genes are missing in b. abortus and that all the polysaccharides described in ... | 1999 | 10338472 |
| protection against development of otitis media induced by nontypeable haemophilus influenzae by both active and passive immunization in a chinchilla model of virus-bacterium superinfection. | three separate studies, two involving active-immunization regimens and one involving a passive-transfer protocol, were conducted to initially screen and ultimately more fully assess several nontypeable haemophilus influenzae outer membrane proteins or their derivatives for their relative protective efficacy in chinchilla models of otitis media. initial screening of these antigens (p5-fimbrin, lipoprotein d, and p6), delivered singly or in combination with either freund's adjuvant or alum, indica ... | 1999 | 10338477 |
| suppression of platelet aggregation by bordetella pertussis adenylate cyclase toxin. | the effect of bordetella pertussis adenylate cyclase toxin (act) on platelet aggregation was investigated. this cell-invasive adenylate cyclase completely suppressed adp (10 microm)-induced aggregation of rabbit platelets at 3 micrograms/ml and strongly suppressed thrombin (0. 2 u/ml)-induced aggregation at 10 micrograms/ml. the suppression was accompanied by marked increase in platelet intracellular cyclic amp (camp) content and was diminished by the anti-act monoclonal antibody b7e11. a cataly ... | 1999 | 10338478 |
| environmental modulation of oral treponeme virulence in a murine model. | this investigation examined the effects of environmental alteration on the virulence of the oral treponemes treponema denticola and treponema pectinovorum. the environmental effects were assessed by using a model of localized inflammatory abscesses in mice. in vitro growth of t. denticola and t. pectinovorum as a function of modification of the cysteine concentration significantly enhanced abscess formation and size. in contrast, growth of t. denticola or t. pectinovorum under iron-limiting cond ... | 1999 | 10338481 |
| antigenic and molecular conservation of the gonococcal nspa protein. | a low-molecular-weight protein named nspa (neisserial surface protein a) was recently identified in the outer membrane of all neisseria meningitidis strains tested. antibodies directed against this protein were shown to protect mice against an experimental meningococcal infection. hybridization experiments clearly demonstrated that the nspa gene was also present in the genomes of the 15 neisseria gonorrhoeae strains tested. cloning and sequencing of the nspa gene of n. gonorrhoeae b2 revealed an ... | 1999 | 10338491 |
| anthrax toxin entry into polarized epithelial cells. | we examined the entry of anthrax edema toxin (edtx) into polarized human t84 epithelial cells using cyclic amp-regulated cl- secretion as an index of toxin entry. edtx is a binary a/b toxin which self assembles at the cell surface from anthrax edema factor and protective antigen (pa). pa binds to cell surface receptors and delivers ef, an adenylate cyclase, to the cytosol. edtx elicited a strong cl- secretory response when it was applied to the basolateral surface of t84 cells but no response wh ... | 1999 | 10338515 |
| helicobacter pylori-associated gastritis in mice is host and strain specific. | the vaca and caga geno- and phenotypes of two mouse-adapted strains of helicobacter pylori, ss1 and spm326, were determined. the ss1 strain, which had the caga+ and vaca s2-m2 genotype, induced neither vacuole formation in hela cells nor interleukin-8 (il-8) production in kato iii cells. in contrast, h. pylori spm326, with the caga+ and vaca s1b-m1 genotype, induced vacuoles as well as il-8 production in vitro. furthermore, a spontaneous mutant of spm326, which produced a vacuolating cytotoxin b ... | 1999 | 10338517 |
| variation in the bordetella pertussis virulence factors pertussis toxin and pertactin in vaccine strains and clinical isolates in finland. | there is evidence that pertussis is reemerging in vaccinated populations. we have proposed, and provided evidence for, one explanation for this phenomenon in the netherlands: antigenic divergence between vaccine strains and circulating strains. finland has a pertussis vaccination history very similar to that of the netherlands, and yet there is no evidence for an increase in the incidence of pertussis to the extent that it was observed in the netherlands. a comparison of the bordetella pertussis ... | 1999 | 10338531 |
| genetic characterization of wild-type and mutant fur genes of bordetella avium. | for most, if not all, organisms, iron (fe) is an essential element. in response to the nutritional requirement for fe, bacteria evolved complex systems to acquire the element from the environment. the genes encoding these systems are often coordinately regulated in response to the fe concentration. recent investigations revealed that bordetella avium, a respiratory pathogen of birds, expressed a number of fe-regulated genes (t. d. connell, a. dickenson, a. j. martone, k. t. militello, m. j. fili ... | 1999 | 10338537 |
| respiratory diseases among u.s. military personnel: countering emerging threats. | emerging respiratory disease agents, increased antibiotic resistance, and the loss of effective vaccines threaten to increase the incidence of respiratory disease in military personnel. we examine six respiratory pathogens (adenoviruses, influenza viruses, streptococcus pneumoniae, streptococcus pyogenes, mycoplasma pneumoniae, and bordetella pertussis) and review the impact of the diseases they cause, past efforts to control these diseases in u.s. military personnel, as well as current treatmen ... | 1999 | 10341174 |
| function of proline residues of mota in torque generation by the flagellar motor of escherichia coli. | bacterial flagellar motors obtain energy for rotation from the membrane gradient of protons or, in some species, sodium ions. the molecular mechanism of flagellar rotation is not understood. mota and motb are integral membrane proteins that function in proton conduction and are believed to form the stator of the motor. previous mutational studies identified two conserved proline residues in mota (pro 173 and pro 222 in the protein from escherichia coli) and a conserved aspartic acid residue in m ... | 1999 | 10348868 |
| cerebellar ataxia following whooping cough. | bordetella pertussis (bp), the agent of whooping cough, has not been recognized so far as a cause of permanent cerebellar ataxia in human. we describe three patients who developed a disabling and permanent cerebellar syndrome soon after whooping cough. in two patients, diagnosis of bp infection was confirmed by culture of nasopharyngeal secretions. the infection occurred between the age of 13 and 15 years, with neurological symptoms beginning after a delay varying from 3 weeks to 3 months. in ou ... | 1999 | 10350207 |
| release of outer membrane vesicles from bordetella pertussis. | the aim of the study reported here was to investigate the production of bordetella pertussis outer membrane vesicles (omvs). numerous vesicles released from cells grown in stainer-scholte liquid medium were observed. the formation of similar vesicle-like structures could also be artificially induced by sonication of concentrated bacterial suspensions. immunoblot analysis showed that omvs contain adenylate cyclase-hemolysin (ac-hly), among other polypeptides, as well as the lipopolysaccharide (lp ... | 1999 | 10355115 |
| [adenylyl cyclase--isoforms, regulation and function]. | since its discovery in 1956, cyclic amp (camp) has been shown to be a ubiquitous second messenger. it functions as one of many signaling molecules enabling cells to respond to external signals. camp is synthesized by adenylyl cyclases (acs), enzymes that convert adenosine triphosphate (atp) to camp. three classes of acs have been cloned based on the conservation of their catalytic domains; they include: class i-acs from enterobacteria, including escherichia coli; class ii-"toxic" acs, including ... | 1999 | 10355282 |
| pseudomonas syringae phytotoxins: mode of action, regulation, and biosynthesis by peptide and polyketide synthetases. | coronatine, syringomycin, syringopeptin, tabtoxin, and phaseolotoxin are the most intensively studied phytotoxins of pseudomonas syringae, and each contributes significantly to bacterial virulence in plants. coronatine functions partly as a mimic of methyl jasmonate, a hormone synthesized by plants undergoing biological stress. syringomycin and syringopeptin form pores in plasma membranes, a process that leads to electrolyte leakage. tabtoxin and phaseolotoxin are strongly antimicrobial and func ... | 1999 | 10357851 |
| pas domains: internal sensors of oxygen, redox potential, and light. | pas domains are newly recognized signaling domains that are widely distributed in proteins from members of the archaea and bacteria and from fungi, plants, insects, and vertebrates. they function as input modules in proteins that sense oxygen, redox potential, light, and some other stimuli. specificity in sensing arises, in part, from different cofactors that may be associated with the pas fold. transduction of redox signals may be a common mechanistic theme in many different pas domains. pas pr ... | 1999 | 10357859 |
| distinct variants of helicobacter pylori caga are associated with vaca subtypes. | the diversity of the cytotoxin-associated gene (caga) of helicobacter pylori was analyzed in 45 isolates obtained from nine countries. we examined variation in the 5' end of the caga open reading frame as determined by pcr and sequencing. phylogenetic analysis revealed the existence of at least two distinct types of caga. one variant (caga1) was found exclusively in strains from europe, the united states, and australia, whereas a novel variant (caga2) was found in strains from east asia. the gre ... | 1999 | 10364602 |
| the morphological transition of helicobacter pylori cells from spiral to coccoid is preceded by a substantial modification of the cell wall. | the peptidoglycan (murein) of helicobacter pylori has been investigated by high-performance liquid chromatography and mass spectrometric techniques. murein from h. pylori corresponded to the a1gamma chemotype, but the muropeptide elution patterns were substantially different from the one for escherichia coli in that the former produced high proportions of muropeptides with a pentapeptide side chain (about 60 mol%), with gly residues as the c-terminal amino acid (5 to 10 mol%), and with (1-->6)an ... | 1999 | 10368145 |
| bacterioferritin a modulates catalase a (kata) activity and resistance to hydrogen peroxide in pseudomonas aeruginosa. | we have cloned a 3.6-kb genomic dna fragment from pseudomonas aeruginosa harboring the rpoa, rplq, kata, and bfra genes. these loci are predicted to encode, respectively, (i) the alpha subunit of rna polymerase; (ii) the l17 ribosomal protein; (iii) the major catalase, kata; and (iv) one of two iron storage proteins called bacterioferritin a (bfra; cytochrome b1 or b557). our goal was to determine the contributions of kata and bfra to the resistance of p. aeruginosa to hydrogen peroxide (h2o2). ... | 1999 | 10368148 |
| identification of two new proteins in spermidine nucleoids isolated from escherichia coli. | the escherichia coli nucleoid contains dna in a condensed but functional form. analysis of proteins released from isolated spermidine nucleoids after treatment with dnase i reveals significant amounts of two proteins not previously detected in wild-type e. coli. partial amino-terminal sequencing has identified them as the products of rdgc and yejk. these proteins are strongly conserved in gram-negative bacteria, suggesting that they have important cellular roles. | 1999 | 10368163 |
| cytotoxic t-lymphocyte epitopes fused to anthrax toxin induce protective antiviral immunity. | we have investigated the use of the protective antigen (pa) and lethal factor (lf) components of anthrax toxin as a system for in vivo delivery of cytotoxic t-lymphocyte (ctl) epitopes. during intoxication, pa directs the translocation of lf into the cytoplasm of mammalian cells. here we demonstrate that antiviral immunity can be induced in balb/c mice immunized with pa plus a fusion protein containing the n-terminal 255 amino acids of lf (lfn) and an epitope from the nucleoprotein (np) of lymph ... | 1999 | 10377103 |
| fatal granuloma necrosis without exacerbated mycobacterial growth in tumor necrosis factor receptor p55 gene-deficient mice intravenously infected with mycobacterium avium. | the pathogenesis of mycobacterial infections is associated with the formation of granulomas in which both antibacterial protection and tissue damage take place concomitantly. we used murine mycobacterium avium infection to compare the development of granulomatous lesions in intravenously infected tumor necrosis factor receptor p55 (tnfrp55) gene-deficient (p55(-/-)) mice to the development of granulomatous lesions in m. avium-infected syngeneic c57bl/6 (p55(+/+)) mice. up to 5 weeks after infect ... | 1999 | 10377141 |
| human monocytic u937 cells kill salmonella in vitro by no-independent mechanisms. | nitric oxide (no) has a central role in host defense against intracellular microbes. hla-b27 has been shown to directly modulate host-microbe interaction in vitro, leading to the impaired elimination of salmonella in human monocytic u937 cells. here, we studied whether impaired elimination of salmonella would result from differences in no production between hla-b27- and hla-a2-transfected u937 cells. both human monocytic transfectants produced no equally well and killed salmonella via no-indepen ... | 1999 | 10377158 |
| secretory phospholipase a2 induces phospholipase cgamma-1 activation and ca2+ mobilization in the human astrocytoma cell line 1321n1 by a mechanism independent of its catalytic activity. | the effect of secretory phospholipase a2 (spla2) on intracellular ca2+ signaling in human astrocytoma cells was studied. spla2 increased cytosolic [ca2+] ([ca2+]c) in both ca2+-containing and ca2+-free medium, thus suggesting ca2+ release from intracellular stores. the activation by spla2 of arachidonate release via cytosolic pla2 (cpla2) was also independent of extracellular ca2+. as spla2 requires ca2+ for activity, these results indicate that both ca2+ mobilization and cpla2 activation induce ... | 1999 | 10381350 |
| dimerization of the agrobacterium tumefaciens virb4 atpase and the effect of atp-binding cassette mutations on the assembly and function of the t-dna transporter. | the agrobacterium tumefaciens virb4 atpase functions with other virb proteins to export t-dna to susceptible plant cells and other dna substrates to a variety of prokaryotic and eukaryotic cells. previous studies have demonstrated that virb4 mutants with defects in the walker a nucleotide-binding motif are non-functional and exert a dominant negative phenotype when synthesized in wild-type cells. this study characterized the oligomeric structure of virb4 and examined the effects of walker a sequ ... | 1999 | 10383764 |
| analysis of peptidoglycan structure from vegetative cells of bacillus subtilis 168 and role of pbp 5 in peptidoglycan maturation. | the composition and fine structure of the vegetative cell wall peptidoglycan from bacillus subtilis were determined by analysis of its constituent muropeptides. the structures of 39 muropeptides, representing 97% of the total peptidoglycan, were elucidated. about 99% analyzed muropeptides in b. subtilis vegetative cell peptidoglycan have the free carboxylic group of diaminopimelic acid amidated. anhydromuropeptides and products missing a glucosamine at the nonreducing terminus account for 0.4 an ... | 1999 | 10383963 |
| characterization of the moraxella catarrhalis uspa1 and uspa2 genes and their encoded products. | the uspa1 and uspa2 genes of m. catarrhalis o35e encode two different surface-exposed proteins which were previously shown to share a 140-amino-acid region with 93% identity (c. aebi, i. maciver, j. l. latimer, l. d. cope, m. k. stevens, s. e. thomas, g. h. mccracken, jr., and e. j. hansen, infect. immun. 65:4367-4377, 1997). the n-terminal amino acid sequences of the mature forms of both uspa1 and uspa2 from strain o35e were determined after enzymatic treatment to remove the n-terminal pyroglut ... | 1999 | 10383971 |
| an epidemic of pertussis among elderly people in a religious institution in the netherlands. | an epidemic of pertussis is described among elderly people in a religious institution in the netherlands in 1992. subjects were evaluated for their vaccination status and for history and presence of respiratory symptoms. specimens were collected for culture, polymerase chain reaction, and serological evaluation. none of the 75 residents and 19 of 24 nonresident personnel had been vaccinated against pertussis. the overall attack rate of clinical pertussis, defined as persistent cough lasting at l ... | 1999 | 10385011 |
| short-term treatment of pertussis with azithromycin in infants and young children. | a prospective, open, noncomparative study was conducted to assess the efficacy and safety of azithromycin given once daily for 3 or 5 days to eradicate bordetella pertussis from the upper respiratory tract of infants and young children. seventeen children received azithromycin in a dose of 10 mg/kg on day 1 followed by 5 mg/kg once daily for four consecutive days, and 20 were given 10 mg/kg once daily for 3 days. seven days after the initiation of therapy, 33 of 35 (94.3%) patients had negative ... | 1999 | 10385021 |
| treatment of severe pertussis: a study of the safety and pharmacology of intravenous pertussis immunoglobulin. | pertussis in infants is often severe, resulting in complications and prolonged hospitalization. treatment is limited to supportive care. antibiotics do not significantly alter the course of the disease. therapies directed at pertussis toxin, a major virulence factor of bordetella pertussis, might be beneficial. this study examines the safety and pharmacology of intravenous pertussis immunoglobulin (p-igiv), which has high levels of pertussis toxin antibodies. | 1999 | 10391179 |
| protective effects of pertussis immunoglobulin (p-igiv) in the aerosol challenge model. | pertussis in infants is often severe, resulting in prolonged hospitalization. treatment is limited to supportive care. antibiotics do not significantly alter the course of the disease unless administered during the catarrhal phase. therapies directed at pertussis toxin, a major virulence factor of bordetella pertussis, may be beneficial. this study uses the aerosol challenge model to further examine the protective effects of p-igiv, a new intravenous immunoglobulin product, which has high levels ... | 1999 | 10391844 |
| outcomes of bordetella infections in vaccinated children: effects of bacterial number in the nasopharynx and patient age. | five outbreaks of infection (three pertussis, one parapertussis, and one mixed) in schools were studied prospectively. nasopharyngeal swabs were obtained from a total of 697 children for culture of bordetella organisms. of 50 vaccinated children with culture-confirmed bordetella infections (29 with pertussis and 21 parapertussis), 40 were symptomatic and 10 remained symptom-free. smaller numbers of colonies were recovered from the nasopharyngeal swabs of the asymptomatic children than from those ... | 1999 | 10391857 |
| intranasal murine model of bordetella pertussis infection. i. prediction of protection in human infants by acellular vaccines. | bicomponent, tricomponent and pertactin dtpa vaccines were tested in sublethal aerosol, and lethal and sublethal intranasal murine bordetella pertussis respiratory challenge models. pertactin and bicomponent vaccines induced protective immunity against lethality but with little or no bacterial clearance. intranasal challenge discriminated in a reproducible, statistically significant manner between the efficacies of bicomponent and tricomponent dtpa, in agreement with clinical trial data. this di ... | 1999 | 10392618 |
| characterization of the serogroup o11 o-antigen locus of pseudomonas aeruginosa pa103. | we previously cloned a genomic dna fragment from the serogroup o11 pseudomonas aeruginosa strain pa103 that contained all genes necessary for o-antigen synthesis and directed the expression of serogroup o11 antigen on recombinant escherichia coli and salmonella. to elucidate the pathway of serogroup o11 antigen synthesis, the nucleotide sequence of the biosynthetic genes was determined. eleven open reading frames likely to be involved in serogroup o11 o-antigen biosynthesis were identified and a ... | 1999 | 10400585 |
| regulated expression of a highly conserved regulatory gene cluster is necessary for controlling photosynthesis gene expression in response to anaerobiosis in rhodobacter capsulatus. | we utilized primer extension analysis to demonstrate that the divergently transcribed regb and senc-rega-hvra transcripts contain stable 5' ends 43 nucleotides apart within the regb-senc intergenic region. dna sequence analysis indicates that this region contains two divergent promoters with overlapping sigma70 type -35 and -10 promoter recognition sequences. in vivo analysis of expression patterns of regb::lacz and senc-rega-hvra::lacz reporter gene fusions demonstrates that the regb and senc-r ... | 1999 | 10400592 |
| mutagenesis of the agrobacterium vire2 single-stranded dna-binding protein identifies regions required for self-association and interaction with vire1 and a permissive site for hybrid protein construction. | the vire2 single-stranded dna-binding protein (ssb) of agrobacterium tumefaciens is required for delivery of t-dna to the nuclei of susceptible plant cells. by yeast two-hybrid and immunoprecipitation analyses, vire2 was shown to self-associate and to interact with vire1. vire2 mutants with small deletions or insertions of a 31-residue oligopeptide (i31) at the n or c terminus or with an i31 peptide insertion at leu236 retained the capacity to form homomultimers. by contrast, vire2 mutants with ... | 1999 | 10400593 |
| identification and complementation of frameshift mutations associated with loss of cytadherence in mycoplasma pneumoniae. | mycoplasma pneumoniae cytadherence is mediated by a specialized, polar attachment organelle. certain spontaneously arising cytadherence mutants (designated class i) lack hmw2, fail to localize the adhesin protein p1 to the attachment organelle, and exhibit accelerated turnover of proteins hmw1, hmw3, and p65. insertional inactivation of hmw2 by tn4001 results in a phenotype nearly identical to that of the class i mutants, suggesting that the latter may result from a defect in hmw2. in this study ... | 1999 | 10400600 |
| augmented acetylcholine-induced, rho-mediated ca2+ sensitization of bronchial smooth muscle contraction in antigen-induced airway hyperresponsive rats. | treatment with acetylcholine (ach) of a beta-escin-permeabilized intrapulmonary bronchial smooth muscle of the rat induced force when the ca2+ concentration was clamped at 1 microm. the ach-induced ca2+ sensitization of myofilaments was significantly greater in antigen-induced airway hyperresponsive rats than in control rats. the ach-induced ca2+ sensitization was completely blocked by treatment with clostridium botulinum c3 exoenzyme, an inactivator of rho family of proteins. moreover, the prot ... | 1999 | 10401547 |
| bactericidal activity of rat lung lavage fluid against bordetella pertussis. | cell-free lung lavage fluid (llf) from healthy normal rats killed phase i (wild-type, virulent) bordetella pertussis at 37 degrees c in vitro. b. parapertussis was also killed by the llf, but phase iv (avirulent mutant) b. pertussis and some other common bacterial species, including b. bronchiseptica, were not. transmission electron microscopy of thin sections of the phase i b. pertussis showed extensive structural damage and cell lysis. none of the other mammalian species tested had llf with ba ... | 1999 | 10403414 |
| tumor-targeted il-2 amplifies t cell-mediated immune response induced by gene therapy with single-chain il-12. | induction, maintenance, and amplification of tumor-protective immunity after cytokine gene therapy is essential for the clinical success of immunotherapeutic approaches. we investigated whether this could be achieved by single-chain il-12 (scil-12) gene therapy followed by tumor-targeted il-2 using a fusion protein containing a tumor-specific recombinant anti-ganglioside gd(2) antibody and il-2 (ch14.18-il-2) in a poorly immunogenic murine neuroblastoma model. herein, we demonstrate the absence ... | 1999 | 10411920 |
| identification of functional domains of bordetella dermonecrotizing toxin. | bordetella dermonecrotizing toxin (dnt) stimulates the assembly of actin stress fibers and focal adhesions by deamidating gln63 of the small gtpase rho. to clarify the functional and structural organization of dnt, we cloned and sequenced the dnt gene and examined the functions of various dnt mutants. our analyses of the nucleotide and amino acid sequences revealed that the start codon of the dnt gene is a gtg triplet located 39 bp upstream of the reported putative initiation atg codon; conseque ... | 1999 | 10417130 |
| target cell range of haemophilus ducreyi hemolysin and its involvement in invasion of human epithelial cells. | haemophilus ducreyi, the causative agent of chancroid, produces a hemolysin, whose role in virulence is not well defined. to assess the possible role of hemolysin in pathogenesis, we evaluated its target cell range by using wild-type h. ducreyi 35000, nonhemolytic mutants with the hemolysin structural gene deleted, and isogenic strains expressing different amounts of hemolytic activity. the cytotoxicity of the various cell types was assessed by quantitating the release of lactate dehydrogenase i ... | 1999 | 10417132 |
| genetic basis for lipopolysaccharide o-antigen biosynthesis in bordetellae. | bordetella bronchiseptica and bordetella parapertussis express a surface polysaccharide, attached to a lipopolysaccharide, which has been called o antigen. this structure is absent from bordetella pertussis. we report the identification of a large genetic locus in b. bronchiseptica and b. parapertussis that is required for o-antigen biosynthesis. the locus is replaced by an insertion sequence in b. pertussis, explaining the lack of o-antigen biosynthesis in this species. the dna sequence of the ... | 1999 | 10417135 |
| prior immunity to homologous and heterologous salmonella serotypes suppresses local and systemic anti-fragment c antibody responses and protection from tetanus toxin in mice immunized with salmonella strains expressing fragment c. | we have investigated the effect of preexisting immunity to homologous (salmonella typhimurium) or heterologous (s. dublin) serotypes of salmonella on the ability of an attenuated s. typhimurium aroa arod vector (brd509) to immunize mice against the heterologous antigen fragment c (frgc). we studied two strains, brd847 and brd937, expressing frgc carried on plasmids that differ only with respect to the promoter controlling frgc expression, the nirb promoter in the case of brd847 and the htra prom ... | 1999 | 10417142 |
| multiple genes in the left half of the cag pathogenicity island of helicobacter pylori are required for tyrosine kinase-dependent transcription of interleukin-8 in gastric epithelial cells. | helicobacter pylori strains that contain the cag pathogenicity island (pai) elicit increased synthesis of gastric c-x-c chemokines, promote neutrophilic infiltration into the gastric epithelium, and stimulate the synthesis of interleukin-8 (il-8) in cultured gastric epithelial cells. to investigate the effects of cag pai genes on the transcription of the il-8 gene, the kato-3 gastric epithelial cell line was stably transfected with plasmid dna containing the il-8 gene promoter fused to a lucifer ... | 1999 | 10417153 |
| cell-mediated immune responses in four-year-old children after primary immunization with acellular pertussis vaccines. | cell-mediated immune (cmi) responses to bordetella pertussis antigens (pertussis toxin [pt], pertactin [prn], and filamentous hemagglutinin [fha]) were assessed in 48-month-old recipients of acellular pertussis [ap] vaccines (either from chiron-biocine [ap-cb] or from smithkline beecham [ap-sb]) and compared to cmi responses to the same antigens at 7 months of age, i.e., 1 month after completion of the primary immunization cycle. none of the children enrolled in this study received any booster o ... | 1999 | 10417175 |
| identification of a glycoprotein produced by enterotoxigenic escherichia coli. | enterotoxigenic escherichia coli (etec) strain h10407 is capable of invading epithelial cell lines derived from the human ileocecum and colon in vitro. two separate chromosomally encoded invasion loci (tia and tib) have been cloned from this strain. these loci direct nonadherent and noninvasive laboratory strains of e. coli to adhere to and invade cultured human intestinal epithelial cells. the tib locus directs the synthesis of tiba, a 104-kda outer membrane protein that is directly correlated ... | 1999 | 10417177 |
| comparative analysis of legionella pneumophila and legionella micdadei virulence traits. | while the majority of legionnaire's disease has been attributed to legionella pneumophila, legionella micdadei can cause a similar infection in immunocompromised people. consistent with its epidemiological profile, the growth of l. micdadei in cultured macrophages is less robust than that of l. pneumophila. to identify those features of the legionella spp. which are correlated to efficient growth in macrophages, two approaches were taken. first, a phenotypic analysis compared four clinical isola ... | 1999 | 10417184 |
| opacity-associated protein a contributes to the binding of haemophilus influenzae to chang epithelial cells. | opacity-associated protein a (oapa), which is responsible for the transparent-colony phenotype of haemophilus influenzae, has been implicated in the colonization of the nasopharynx in an infant rat model of carriage. in this report, we show that oapa mediates attachment to chang epithelial cells examined by using genetically defined type b and nontypeable h. influenzae strains with or without oapa. we also showed that oapa was conserved among h. influenzae strains by comparing deduced amino acid ... | 1999 | 10417187 |
| fluorescent labels influence phagocytosis of bordetella pertussis by human neutrophils. | to explore the role of neutrophil phagocytosis in host defense against bordetella pertussis, bacteria were labeled extrinsically with fluorescein isothiocyanate (fitc) or genetically with green fluorescent protein (gfp) and incubated with adherent human neutrophils in the presence or absence of heat-inactivated human immune serum. in the absence of antibodies, fitc-labeled bacteria were located primarily on the surface of the neutrophils with few bacteria ingested. however, after opsonization, a ... | 1999 | 10417202 |
| intranasal murine model of bordetella pertussis infection: ii. sequence variation and protection induced by a tricomponent acellular vaccine. | when pertussis toxin s1 subunit and pertactin structural genes in bordetella pertussis clinical isolates from france and germany were sequenced, 3 previously described s1 subunit types (s1 a, b and e), and 4 pertactin types (prn a, b, c, a*) were found. prn a*, present in the who reference strain 18323, was not described previously. in a respiratory mouse model, a tricomponent acellular pertussis vaccine (infanrix) was highly effective in promoting lung clearance of all isolates expressing diffe ... | 1999 | 10418915 |
| transcriptional activation of agrobacterium tumefaciens virulence gene promoters in escherichia coli requires the a. tumefaciens rpoa gene, encoding the alpha subunit of rna polymerase. | the two-component regulatory system, composed of vira and virg, is indispensable for transcription of virulence genes within agrobacterium tumefaciens. however, vira and virg are insufficient to activate transcription from virulence gene promoters within escherichia coli cells, indicating a requirement for additional a. tumefaciens genes. in a search for these additional genes, we have identified the rpoa gene, encoding the alpha subunit of rna polymerase (rnap), which confers significant expres ... | 1999 | 10419950 |
| effect of different levels of intracellular camp on the in vitro maturation of cattle oocytes and their subsequent development following in vitro fertilization. | serum, gonadotrophins, growth factors, and steroid hormones stimulate the in vitro maturation (ivm) of competent oocytes, acting, directly or indirectly, upon the adenylate cyclase pathway to produce the intracellular messenger, camp. the intracellular levels of camp in cattle cumulus-oocyte complexes (coc) were manipulated by adding to the collection and maturation media invasive adenylate cyclase (iac), a toxin produced by the bacterium, bordetella pertussis. high concentrations of iac (1 or 5 ... | 1999 | 10423303 |
| characterization of bordetella pertussis strains of recent isolation. | during the clinical trial conducted in italy to evaluate the efficacy of new acellular pertussis vaccines, the most favorable conditions for the recovery and characterization of bordetella pertussis strains, isolated from children with cough, were adopted. the nasopharyngeal aspirates were collected and sent to the laboratory in refrigerated conditions within 24 hours. charcoal agar selective and non selective plates were used, and most of the isolates were recovered after 3-4 days of incubation ... | 1999 | 10423736 |
| interferon-gamma mediated immune effector mechanisms against bordetella pertussis. | the role of ifn-gamma in reducing the intracellular load of bordetella pertussis in murine macrophages in vitro has been examined. the results demonstrate that exposure to ifn-gamma can reduce bacterial load in viable macrophages and that this is associated with production of nitric oxide (no). these observations provide a mechanism by which ifn-gamma may mediate its antimicrobial effect and support an important role for activated alveolar macrophages in the elimination of b. pertussis from the ... | 1999 | 10424423 |
| identification of the yqhe and yafb genes encoding two 2, 5-diketo-d-gluconate reductases in escherichia coli. | the identification of a gene (yiae) encoding 2-ketoaldonate reductase (2kr) in our previous work led to the hypothesis that escherichia coli has other ketogluconate reductases including 2, 5-diketo-d-gluconate reductase (25dkgr) and to study of the related ketogluconate metabolism. by using the deduced amino acid sequences of 5-diketo-d-gluconate reductase (5kdgr) of gluconobacter oxydans and 25dkgr of corynebacterium sp., protein databases were screened to detect homologous proteins. among the ... | 1999 | 10427017 |
| a highly conserved sequence is a novel gene involved in de novo vitamin b6 biosynthesis. | the cercospora nicotianae sor1 (singlet oxygen resistance) gene was identified previously as a gene involved in resistance of this fungus to singlet-oxygen-generating phototoxins. although homologues to sor1 occur in organisms in four kingdoms and encode one of the most highly conserved proteins yet identified, the precise function of this protein has, until now, remained unknown. we show that sor1 is essential in pyridoxine (vitamin b6) synthesis in c. nicotianae and aspergillus flavus, althoug ... | 1999 | 10430950 |
| in vitro susceptibilities of bordetella pertussis and bordetella parapertussis to the novel oxazolidinones eperezolid (pnu-100592) and linezolid (pnu-100766) | | 1999 | 10435686 |
| essential components of the ti plasmid trb system, a type iv macromolecular transporter. | the trb operon from ptic58 is one of three loci that are required for conjugal transfer of this ti plasmid. the operon, which probably codes for the mating bridge responsible for pair formation and dna transfer, contains 12 genes, 11 of which are related to genes from other members of the type iv secretion system family. the 12th gene, trai, codes for production of agrobacterium autoinducer (aai). insertion mutations were constructed in each of the 12 genes, contained on a full-length clone of t ... | 1999 | 10438776 |
| physical mapping of the autoimmune disease susceptibility locus, bphs: co-localization with a cluster of genes from the tnf receptor superfamily on mouse chromosome 6. | an important approach to understanding complex diseases is to reduce them into well-characterized subphenotypes that are under monogenic control. one such example is bordetella pertussis toxin-induced histamine sensitization in mice, a subphenotype of experimental allergic encephalomyelitis and experimental allergic orchitis. this subphenotype is controlled by a single locus, bphs, previously mapped to a 33 cm region on mouse chromosome (chr) 6. we achieved considerable reduction of this candida ... | 1999 | 10441735 |
| a commentary on the pathogenesis of pertussis. | in recent years a great deal of information has been generated on the virulence factors produced by bordetella pertussis, the regulation of their expression, and their molecular mechanisms of action. there are numerous studies of bordetella virulence factors and strains of b. pertussis in which the genes for some of these components have been mutated or deleted. in addition, several acellular vaccines composed of these virulence factors have been developed, tested, and licensed for use in the pr ... | 1999 | 10447025 |
| microbiological and serological diagnosis of pertussis. | swedish vaccine trials have been used to examine sensitivity and specificity of diagnostic procedures for bordetella pertussis infection. the proportions of cases diagnosed by culture and serology were 55% and 45%, respectively, when both methods were optimized. the culture method included nasopharyngeal aspiration, direct inoculation on plates, enrichment, and repeated collection of samples. an enzyme-linked immunosorbent assay for igg antibodies to pertussis toxin (pt) and to filamentous hemag ... | 1999 | 10447026 |
| epidemiological, clinical, and laboratory aspects of pertussis in adults. | in populations without immunization, pertussis is a high-incidence, endemic disease with cyclic epidemic peaks occurring every 2-5 years. the universal use of pertussis vaccines in children results in a marked reduction in incidence, but the frequency of disease cycles does not lengthen. this indicates that the organism (bordetella pertussis) remains prevalent in the population. studies of prolonged cough illnesses in adolescents and adults indicate that between 12% and 32% are the result of b. ... | 1999 | 10447028 |
| cellular and acellular pertussis vaccines in adults. | immunization against pertussis after childhood previously was considered unnecessary, because severe illness and complications rarely developed in older persons. the rising incidence of pertussis among older adolescents and adults and the transmission of infection from adults to infants suggest that booster immunization may be necessary to more effectively control pertussis in all age groups. whole cell pertussis vaccines are regarded as unsuitable for routine use in adults because of reports of ... | 1999 | 10447029 |
| comparison of pcr, culture, and direct fluorescent-antibody testing for detection of bordetella pertussis. | we prospectively compared the performance of culture, direct fluorescent-antibody testing (dfa), and an in-house-developed pcr test targeting the repeated insertion sequence is481 for the detection of bordetella pertussis in nasopharyngeal swab specimens. we tested 319 consecutive paired specimens on which all three tests were performed. a total of 59 specimens were positive by one or more tests. of these, 5 were positive by all three tests, 2 were positive by culture and pcr, 16 were positive b ... | 1999 | 10449467 |
| safety and immunogenicity of haemophilus influenzae-tetanus toxoid conjugate vaccine given separately or in combination with a three-component acellular pertussis vaccine combined with diphtheria and tetanus toxoids and inactivated poliovirus vaccine for the first four doses. | the purpose of this randomized, controlled trial was to assess the safety and immunogenicity of a three-component acellular pertussis vaccine combined with diphtheria and tetanus toxoids and inactivated poliovirus vaccine given either separately or combined as a single injection with a haemophilus influenzae type b-tetanus toxoid conjugate vaccine. a total of 180 infants were immunized at 2, 4, and 6 months of age; 129 were given a booster dose at 16-19 months of age. vaccine-associated adverse ... | 1999 | 10452624 |
| intranasal immunization with heat-inactivated streptococcus pneumoniae protects mice against systemic pneumococcal infection. | in order to study the mucosal and serum antibody response to polysaccharide-encapsulated bacteria in mice, a preparation of heat-inactivated streptococcus pneumoniae type 4 was administered, with and without cholera toxin, at various mucosal sites. it appeared that intranasal immunization of nonanesthesized animals was superior to either oral, gastric, or colonic-rectal antigen delivery with regard to the induction of serum immunoglobulin g (igg) and iga, as well as saliva iga antibodies specifi ... | 1999 | 10456869 |
| group a streptococcus induces apoptosis in human epithelial cells. | internalization of group a streptococcus (gas) by epithelial cells may have a role in causing invasive diseases. the purpose of this study was to examine the fate of gas-infected epithelial cells. gas has the ability to invade a-549 and hep-2 cells. both a-549 and hep-2 cells were killed by infection with gas. epithelial cell death mediated by gas was at least in part through apoptosis, as shown by changes in cellular morphology, dna fragmentation laddering, and propidium iodide staining for hyp ... | 1999 | 10456871 |
| host responses to recombinant hemagglutinin b of porphyromonas gingivalis in an experimental rat model. | porphyromonas gingivalis, a gram-negative, black-pigmented anaerobe, is among the microorganisms implicated in the etiology of adult periodontal disease. this bacterium possesses a number of factors, including hemagglutinins, of potential importance in virulence. several hemagglutinin genes have been identified, cloned, and expressed in escherichia coli. the purpose of this study was to characterize host responses to purified recombinant hemagglutinin b (rhag b), using the conventional fischer r ... | 1999 | 10456874 |
| characterization of binding of adenylate cyclase toxin to target cells by flow cytometry. | adenylate cyclase (ac) toxin from bordetella pertussis intoxicates eukaryotic cells by increasing intracellular cyclic amp (camp) levels. in addition, insertion of ac toxin into the plasma membrane causes efflux of intracellular k(+) and, in a related process, hemolysis of sheep erythrocytes. although intoxication, k(+) efflux, and hemolysis have been thoroughly investigated, there is little information on the nature of the interaction of this toxin with intact target cells. using flow cytometry ... | 1999 | 10456879 |
| intracellular growth in acanthamoeba castellanii affects monocyte entry mechanisms and enhances virulence of legionella pneumophila. | since legionella pneumophila is an intracellular pathogen, entry into and replication within host cells are thought to be critical to its ability to cause disease. l. pneumophila grown in one of its environmental hosts, acanthamoeba castellanii, is phenotypically different from l. pneumophila grown on standard laboratory medium (bcye agar). although amoeba-grown l. pneumophila displays enhanced entry into monocytes compared to bcye-grown bacteria, the mechanisms of entry used and the effects on ... | 1999 | 10456883 |
| interaction of leishmania gp63 with cellular receptors for fibronectin. | the most abundant protein on the surface of the promastigote form of the protozoan parasites leishmania spp. is a 63-kda molecule, designated gp63 or leishmanolysin. because gp63 has been shown to possess fibronectin-like properties, we examined the interaction of gp63 with the cellular receptors for fibronectin. we measured the direct binding of leishmania to human macrophages or to transfected mammalian cells expressing human fibronectin receptors. leishmania expressing gp63 exhibited modest b ... | 1999 | 10456889 |
| cell surface-exposed tetanus toxin fragment c produced by recombinant bacillus anthracis protects against tetanus toxin. | bacillus anthracis, the causal agent of anthrax, synthesizes two surface layer (s-layer) proteins, ea1 and sap, which account for 5 to 10% of total protein and are expressed in vivo. a recombinant b. anthracis strain was constructed by integrating into the chromosome a translational fusion harboring the dna fragments encoding the cell wall-targeting domain of the s-layer protein ea1 and tetanus toxin fragment c (toxc). this construct was expressed under the control of the promoter of the s-layer ... | 1999 | 10456940 |
| the 102-kilobase pgm locus of yersinia pestis: sequence analysis and comparison of selected regions among different yersinia pestis and yersinia pseudotuberculosis strains. | we report the complete 119,443-bp sequence of the pgm locus from yersinia pestis and its flanking regions. sequence analysis confirms that the 102-kb unstable pgm locus is composed of two distinct parts: the pigmentation segment and a high-pathogenicity island (hpi) which carries virulence genes involved in iron acquisition (yersiniabactin biosynthetic gene cluster). within the hpi, three genes coding for proteins related to phage proteins were uncovered. they are located at both extremities ind ... | 1999 | 10456941 |
| parapertussis and pertussis: differences and similarities in incidence, clinical course, and antibody responses. | to compare the incidence, clinical course, and serologic response to bordetella antigens in patients with parapertussis and pertussis. | 1999 | 10460925 |
| an acellular pertussis vaccine in healthy adults: safety and immunogenicity. pennridge pediatric associates. | recent data indicate that bordetella pertussis can be an important cause of illness in adolescents and adults. in a randomized observer- and subject-blinded study, adults (> or = 18 years of age) received an acellular pertussis (ap) vaccine containing genetically inactivated pertussis toxin (pt), filamentous hemagglutinin (fha) and pertactin (prn), or a saline placebo, and were monitored for safety and immunogenicity. igg antibodies to pt, fha, and prn were measured by enzyme-linked immunosorben ... | 1999 | 10462235 |
| antigenic variants in bordetella pertussis strains isolated from vaccinated and unvaccinated children. | bordetella pertussis shows polymorphism in two proteins, pertactin (prn) and the pertussis toxin (pt) s1 subunit, which are important for immunity. a previous study has shown antigenic shifts in these proteins in the dutch b. pertussis population, and it was suggested that these shifts were driven by vaccination. the recent italian clinical trial provided the opportunity to compare the frequencies of prn and pt s1 subunit variants in strains isolated from unvaccinated children, and from children ... | 1999 | 10463173 |
| analysis of bvga activation of the pertactin gene promoter in bordetella pertussis. | bordetella pertussis, the causative agent of whooping cough, regulates expression of its virulence factors via a two-component signal transduction system encoded by the bvg regulatory locus. it has been shown by activation kinetics that several of the virulence factors are differentially regulated. fha is transcribed at 10 min following an inducing signal, while ptx is not transcribed until 2 to 4 h after the inducing signal. we present data indicating that prn is transcribed at 1 h, an intermed ... | 1999 | 10464192 |
| the cpx envelope stress response is controlled by amplification and feedback inhibition. | in escherichia coli, the cpx two-component regulatory system activates expression of protein folding and degrading factors in response to misfolded proteins in the bacterial envelope (inner membrane, periplasm, and outer membrane). it is comprised of the histidine kinase cpxa and the response regulator cpxr. this response plays a role in protection from stresses, such as elevated ph, as well as in the biogenesis of virulence factors. here, we show that the cpx periplasmic stress response is subj ... | 1999 | 10464196 |
| genomic plasticity in natural populations of bordetella pertussis. | we determined the genomic organization of 14 clinical strains of bordetella pertussis isolated over an 18-month period in alberta, canada. the maps of these 14 strains, while demonstrating general similarity of gene order, display a number of examples of genomic rearrangements in the form of large chromosomal inversions. | 1999 | 10464229 |
| asiasari radix inhibits immunoglobulin e production on experimental models in vitro and in vivo. | immunoglobulin (ig) e is the principal ig involved in immediate hypersensitivities and chronic allergic diseases. the hallmark of these disorders is increased ige production. the effect of an aqueous extract of the roots of asiasari radix (arae) on an in vivo and in vitro ige production was investigated. arae dose-dependently inhibited the active systemic anaphylaxis and serum ige production induced by immunization with ovalbumin, bordetella pertussis toxin and aluminum hydroxide gel. arae stron ... | 1999 | 10466075 |
| role of interleukin-4 in down-regulation of contact sensitivity by gammadelta t cells from tolerized t-cell receptor alpha-/- mice. | contact sensitivity (cs) is a classical example of an in vivo t-cell-mediated immune response that is under regulation. such down-regulation can be mediated by alphabeta t cells in mice that are tolerized by prior exposure to high doses of antigen. in contrast, we demonstrated previously that such high-dose antigen tolerance in t-cell receptor (tcr) alpha-/- h-2d mice induced antigen-specific, apparently major histocompatibility complex-unrestricted, cd4- cd8- gammadelta t cells, that also could ... | 1999 | 10469235 |
| inhibition of immunoglobulin e production by poncirus trifoliata fruit extract. | immunoglobulin e (ige) is the principal immunoglobulin involved in immediate hypersensitivities and chronic allergic diseases. the effect of an aqueous extract of poncirus trifoliata (l) raf. (rutaceae) fruits (ptfe) on in vivo and in vitro ige production was investigated. ptfe dose-dependently inhibited the active systemic anaphylaxis and serum ige production induced by immunization with ovalbumin, bordetella pertussis toxin and aluminum hydroxide gel. ptfe strongly inhibited interleukin 4 (il- ... | 1999 | 10473174 |
| genetics of o-antigen biosynthesis in pseudomonas aeruginosa. | pathogenic bacteria produce an elaborate assortment of extracellular and cell-associated bacterial products that enable colonization and establishment of infection within a host. lipopolysaccharide (lps) molecules are cell surface factors that are typically known for their protective role against serum-mediated lysis and their endotoxic properties. the most heterogeneous portion of lps is the o antigen or o polysaccharide, and it is this region which confers serum resistance to the organism. pse ... | 1999 | 10477307 |
| metabolism and genetics of helicobacter pylori: the genome era. | the publication of the complete sequence of helicobacter pylori 26695 in 1997 and more recently that of strain j99 has provided new insight into the biology of this organism. in this review, we attempt to analyze and interpret the information provided by sequence annotations and to compare these data with those provided by experimental analyses. after a brief description of the general features of the genomes of the two sequenced strains, the principal metabolic pathways are analyzed. in particu ... | 1999 | 10477311 |
| helicobacter pylori physiology predicted from genomic comparison of two strains. | helicobacter pylori is a gram-negative bacteria which colonizes the gastric mucosa of humans and is implicated in a wide range of gastroduodenal diseases. this paper reviews the physiology of this bacterium as predicted from the sequenced genomes of two unrelated strains and reconciles these predictions with the literature. in general, the predicted capabilities are in good agreement with reported experimental observations. h. pylori is limited in carbohydrate utilization and will use amino acid ... | 1999 | 10477312 |
| interference with the signaling capacity of cc chemokine receptor 5 can compromise its role as an hiv-1 entry coreceptor in primary t lymphocytes. | | 1999 | 10477544 |
| the b-oligomer of pertussis toxin deactivates cc chemokine receptor 5 and blocks entry of m-tropic hiv-1 strains. | infection of target cells by hiv-1 requires initial binding interactions between the viral envelope glycoprotein gp120, the cell surface protein cd4, and one of the members of the seven-transmembrane g protein-coupled chemokine receptor family. most primary isolates (r5 strains) use chemokine receptor ccr5, but some primary syncytium-inducing, as well as t cell line-adapted, strains (x4 strains) use the cxcr4 receptor. signaling from both ccr5 and cxcr4 is mediated by pertussis toxin (ptx)-sensi ... | 1999 | 10477545 |
| migration of antigen-presenting b cells from peripheral to mucosal lymphoid tissues may induce intestinal antigen-specific iga following parenteral immunization. | parenterally administered immunizations have long been used to induce protection from mucosal pathogens such as bordetella pertussis and influenza virus. we previously found that i.m. inoculation of mice with the intestinal pathogen, rotavirus, induced virus-specific ab production by intestinal lymphocytes. we have now used adoptive transfer studies to identify the cell types responsible for the generation of virus-specific ab production by gut-associated lymphoid tissue (galt) after i.m. immuni ... | 1999 | 10477570 |
| bordetella pertussis, bordetella parapertussis, mycoplasma pneumoniae, chlamydia pneumoniae and persistent cough in children. | material collected during a prospective pertussis vaccine trial in 1992-95 was examined for bordetella pertussis (culture and serology), bordetella parapertussis (culture), mycoplasma pneumoniae and chlamydia pneumoniae (pcr). from 64% (99/155) of episodes with cough for less than 100 d, 115 aetiological agents were identified in one southern and one northern subset of dt-recipients. the most common single agent was b. pertussis, representing 56%(64/115), with a median cough period of 51 d, foll ... | 1999 | 10482058 |
| positive transcriptional feedback controls hydrogenase expression in alcaligenes eutrophus h16. | the protein hoxa is the central regulator of the alcaligenes eutrophus h16 hox regulon, which encodes two hydrogenases, a nickel permease and several accessory proteins required for hydrogenase biosynthesis. expression of the regulatory gene hoxa was analyzed. screening of an 8-kb region upstream of hoxa with a promoter probe vector localized four promoter activities. one of these was found in the region immediately 5' of hoxa; the others were correlated with the nickel metabolism genes hypa1, h ... | 1999 | 10482509 |
| the c-terminal domain of the bordetella pertussis autotransporter brka forms a pore in lipid bilayer membranes. | brka is a 103-kda outer membrane protein of bordetella pertussis that mediates resistance to antibody-dependent killing by complement. it is proteolytically processed into a 73-kda n-terminal domain and a 30-kda c-terminal domain as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. brka is also a member of the autotransporter family of proteins. translocation of the n-terminal domain of the protein across the outer membrane is hypothesized to occur through a pore formed by ... | 1999 | 10482528 |
| identification of a functional fur gene in bradyrhizobium japonicum. | the recent identification of the iron response regulator (irr) in bradyrhizobium japonicum raised the question of whether the global regulator fur is present in that organism. a fur gene homolog was isolated by the functional complementation of an escherichia coli fur mutant. the b. japonicum fur bound to a fur box dna element in vitro, and a fur mutant grown in iron-replete medium was derepressed for iron uptake activity. thus, b. japonicum expresses at least two regulators of iron metabolism. | 1999 | 10482529 |
| detection of prosthetic hip infection at revision arthroplasty by immunofluorescence microscopy and pcr amplification of the bacterial 16s rrna gene. | in this study the detection rates of bacterial infection of hip prostheses by culture and nonculture methods were compared for 120 patients with total hip revision surgery. by use of strict anaerobic bacteriological practice during the processing of samples and without enrichment, the incidence of infection by culture of material dislodged from retrieved prostheses after ultrasonication (sonicate) was 22%. bacteria were observed by immunofluorescence microscopy in 63% of sonicate samples with a ... | 1999 | 10488193 |
| immunogenicity and safety of haemophilus influenzae type b conjugate vaccine (hibtiter) and a combination vaccine of diphtheria, tetanus, pertussis and hibtiter (tetramune) in two-month-old infants. | a study was undertaken to evaluate the safety and immunogenicity of a combination vaccine (tetramune) of conjugate haemophilus influenzae type b (hib) vaccine (hibtiter) and dtp (diphtheria, tetanus and pertussis) vaccine. a total of 93 healthy children were randomized to receive either tetramune (combined group), or dtp and hibtiter administered concurrently (separate group) in separate syringes at approximately 2, 4 and 6 months of age in taiwan. serologic responses were largely comparable bet ... | 1998 | 10496155 |
| humoral and cellular immune responses in mice immunized with recombinant mycobacterium bovis bacillus calmette-guérin producing a pertussis toxin-tetanus toxin hybrid protein. | the development of combined vaccines constitutes one of the priorities in modern vaccine research. one of the most successful combined vaccines in use is the diphtheria-pertussis-tetanus vaccine. however, concerns about the safety of the pertussis arm have led to decreased acceptance of the vaccine but also to the development of new, safer, and effective acellular vaccines against pertussis. unfortunately, the production cost of these new vaccines is significantly higher than that of previous va ... | 1999 | 10496883 |
| use of in vivo-regulated promoters to deliver antigens from attenuated salmonella enterica var. typhimurium. | this study describes the construction and analysis of three in vivo-inducible promoter expression plasmids, containing pnirb, ppagc, and pkatg, for the delivery of foreign antigens in the deltaaroad mutant of salmonella enterica var. typhimurium (hereafter referred to as s. typhimurium). the reporter genes encoding beta-galactosidase and firefly luciferase were used to assess the comparative levels of promoter activity in s. typhimurium in vitro in response to different induction stimuli and in ... | 1999 | 10496887 |
| identification of genes in an extraintestinal isolate of escherichia coli with increased expression after exposure to human urine. | the identification of genes with increased expression in vivo may lead to the identification of novel or unrecognized virulence traits and/or recognition of environmental signals involved in modulating gene expression. our laboratory is studying an extraintestinal isolate of escherichia coli as a model pathogen. we had previously used human urine ex vivo to identify the unrecognized urovirulence genes guaa and argc and to establish that arginine and guanine (or derivatives) were limiting in this ... | 1999 | 10496910 |
| fasciola hepatica suppresses a protective th1 response against bordetella pertussis. | fasciolosis, like other helminth infections, is associated with the induction of t-cell responses polarized to the th2 subtype. respiratory infection with bordetella pertussis or immunization with a pertussis whole-cell vaccine (pw) induces a potent th1 response, which confers a high level of protection against bacterial challenge. we have used these two pathogens to examine bystander cross-regulation of th1 and th2 cells in vivo and provide evidence of immunomodulation of host t-cell responses ... | 1999 | 10496919 |
| functional characterization of a serine/threonine protein kinase of pseudomonas aeruginosa. | protein kinases play a key role in signal transduction pathways in both eukaryotic and prokaryotic cells. using in vivo expression technology, we have identified several promoters in pseudomonas aeruginosa which are preferentially activated during infection of neutropenic mice. one of these promoters directs the transcription of a gene encoding a putative protein kinase similar to the enzymes found in eukaryotic cells. the full characterization of this protein, termed ppka, is presented in this ... | 1999 | 10496921 |