| synergistic epithelial responses to endotoxin and a naturally occurring muramyl peptide. | we have investigated the synergistic interactions of a naturally occurring peptidoglycan fragment (muramyl peptide) and bacterial endotoxin in the induction of inflammatory processes within respiratory epithelial cells, at the levels of both signal transduction events and ultimate cellular metabolic effects. the source of the muramyl peptide is bordetella pertussis, the causative agent of the respiratory disease pertussis. during log-phase growth, b. pertussis releases the muramyl peptide trache ... | 2000 | 10678932 |
| mutations in the s1 subunit of pertussis toxin that affect secretion. | pertussis toxin is a member of the ab(5) family of toxins and is composed of five subunits (s1 to s5) present in a 1:1:1:2:1 ratio. secretion is a complex process. each subunit has a secretion signal that mediates transport to the periplasm, where processing and assembly occur. secretion of the assembled 105-kda toxin past the outer membrane is mediated by the nine proteins encoded in the ptl operon. previous studies have shown that s1, the catalytically active a subunit of pertussis toxin, is n ... | 2000 | 10678938 |
| identification of brucella suis genes affecting intracellular survival in an in vitro human macrophage infection model by signature-tagged transposon mutagenesis. | bacteria of the genus brucella are facultative intracellular pathogens which have developed the capacity to survive and multiply in professional and nonprofessional phagocytes. the genetic basis of this aspect of brucella virulence is still poorly understood. to identify new virulence factors, we have adapted signature-tagged transposon mutagenesis, which has been used essentially in animal models, to an in vitro human macrophage infection model. a library of 1,152 brucella suis 1330 tagged mini ... | 2000 | 10678941 |
| a regulatory role for interleukin 4 in differential inflammatory responses in the lung following infection of mice primed with th1- or th2-inducing pertussis vaccines. | protection against infectious pathogens at mucosal surfaces is dependent on local antibody responses, production of inflammatory mediators, and recruitment of immune effector cells to the site of infection. since th1 and th2 cells produce cytokines with pro- and anti-inflammatory activities, immunization with vaccines that induce these t-cell subtypes may regulate the subsequent inflammatory response to infection. we have demonstrated that immunization of mice with pertussis whole-cell or acellu ... | 2000 | 10678951 |
| construction and characterization of a salmonella enterica serovar typhimurium clone expressing a salivary adhesin of streptococcus mutans under control of the anaerobically inducible nirb promoter. | attenuated salmonella enterica serovar typhimurium has been used for targeted delivery of recombinant antigens to the gut-associated lymphoid tissues. one potential problem associated with this vaccine approach is the likelihood of in vivo instability of the plasmid constructs caused by constitutive hyperexpression of the heterologous immunogen. the aim of this study was to generate and characterize an expression system encoding the saliva-binding region (sbr) of streptococcus mutans antigen i/i ... | 2000 | 10678973 |
| bordetella pertussis virulence factors affect phagocytosis by human neutrophils. | the interaction between human neutrophils and wild-type bordetella pertussis or mutants expressing altered lipopolysaccharide or lacking virulence factors-pertussis toxin, adenylate cyclase toxin, dermonecrotic toxin, filamentous hemagglutinin (fha), pertactin, or brka-was examined. in the absence of antibodies, the wild-type strain and the mutants, with the exception of mutants lacking fha, attached efficiently to neutrophils. the addition of opsonizing antibodies caused a significant reduction ... | 2000 | 10679000 |
| detection of bordetella holmesii using bordetella pertussis is481 pcr assay. | | 2000 | 10681208 |
| acetyl-coa synthetase from the amitochondriate eukaryote giardia lamblia belongs to the newly recognized superfamily of acyl-coa synthetases (nucleoside diphosphate-forming). | the gene coding for the acetyl-coa synthetase (adp-forming) from the amitochondriate eukaryote giardia lamblia has been expressed in escherichia coli. the recombinant enzyme exhibited the same substrate specificity as the native enzyme, utilizing acetyl-coa and adenine nucleotides as preferred substrates and less efficiently, propionyl- and succinyl-coa. n- and c-terminal parts of the g. lamblia acetyl-coa synthetase sequence were found to be homologous to the alpha- and beta-subunits, respectiv ... | 2000 | 10681568 |
| [alterations of amino acids in rat cerebral cortex of infectious brain injuries]. | concentrations of amino acids such as glutamate(glu), glutamine(gln), gamma-aminobutyric (gaba), glycerin(gly) in rat cerebral cortex were measured by o-phthaldialdehyde method to clarify alterations of these amino acids in infectious brain injuries(ibi). the results were that gln and gaba in groups treated by bordetella pertussis suspension(bp) 4h were increased compared to those in the group treated by the normal saline(ns) or the operative control(oc) and a positive correlation with water con ... | 1998 | 10682551 |
| helicobacter pylori caga protein can be tyrosine phosphorylated in gastric epithelial cells. | attachment of helicobacter pylori to gastric epithelial cells induces various cellular responses, including the tyrosine phosphorylation of an unknown 145-kd protein and interleukin 8 production. here we show that this 145-kd protein is the caga product of h. pylori, an immunodominant, cytotoxin-associated antigen. epithelial cells infected with various h. pylori clinical isolates resulted in generation of tyrosine-phosphorylated proteins ranging from 130 to 145 kd in size that were also induced ... | 2000 | 10684851 |
| biologic functions of the ifn-gamma receptors. | interferon-gamma (ifn-gamma) is a cytokine that plays an important role in inducing and modulating an array of immune responses. cellular responses to ifn-gamma are mediated by its heterodimeric cell-surface receptor (ifn-gammar), which activates downstream signal transduction cascades, ultimately leading to the regulation of gene expression. in order to study the role of ifn-gamma in a number of immune responses and pathways, researchers have generated mice with altered patterns of ifn-gammar g ... | 1999 | 10688427 |
| trag from rp4 and trag and vird4 from ti plasmids confer relaxosome specificity to the conjugal transfer system of ptic58. | plasmid conjugation systems are composed of two components, the dna transfer and replication system, or dtr, and the mating pair formation system, or mpf. during conjugal transfer an essential factor, called the coupling protein, is thought to interface the dtr, in the form of the relaxosome, with the mpf, in the form of the mating bridge. these proteins, such as trag from the incp1 plasmid rp4 (trag(rp4)) and trag and vird4 from the conjugal transfer and t-dna transfer systems of ti plasmids, a ... | 2000 | 10692358 |
| components of the rp4 conjugative transfer apparatus form an envelope structure bridging inner and outer membranes of donor cells: implications for related macromolecule transport systems. | during bacterial conjugation, the single-stranded dna molecule is transferred through the cell envelopes of the donor and the recipient cell. a membrane-spanning transfer apparatus encoded by conjugative plasmids has been proposed to facilitate protein and dna transport. for the incpalpha plasmid rp4, a thorough sequence analysis of the gene products of the transfer regions tra1 and tra2 revealed typical features of mainly inner membrane proteins. we localized essential rp4 transfer functions to ... | 2000 | 10692361 |
| the right end of the vir region of an octopine-type ti plasmid contains four new members of the vir regulon that are not essential for pathogenesis. | we sequenced the vird-vire, vire-virf, and virf-t-dna intergenic regions of an octopine ti plasmid. four newly described genes were induced by the vir gene inducer acetosyringone, two of which are conserved in the nopaline-type ti plasmid ptic58. one gene resembles a family of phosphatase genes. each of these genes is dispensable for tumorigenesis. | 2000 | 10692388 |
| bordetella pertussis surveillance in england and wales: 1995-7. | available data sources on disease due to bordetella pertussis, including notifications, hospital admissions, deaths, and an enhanced laboratory-based surveillance system commenced in january 1994, were reviewed for the period 1995-7. pertussis notifications continued their approximately 3-year cycle although at historically reduced levels. a slight seasonal increase in late summer/early autumn existed over and above a relatively constant background rate. over time, the proportion of pertussis ca ... | 1999 | 10694150 |
| biosynthesis of terpenoids: ygbb protein converts 4-diphosphocytidyl-2c-methyl-d-erythritol 2-phosphate to 2c-methyl-d-erythritol 2,4-cyclodiphosphate. | in many microorganisms, the putative orthologs of the escherichia coli ygbb gene are tightly linked or fused to putative orthologs of ygbp, which has been shown earlier to be involved in terpenoid biosynthesis. the ygbb gene of e. coli was expressed in a recombinant e. coli strain and was shown to direct the synthesis of a soluble, 17-kda polypeptide. the recombinant protein was found to convert 4-diphosphocytidyl-2c-methyl-d-erythritol 2-phosphate into 2c-methyl-d-erythritol 2,4-cyclodiphosphat ... | 2000 | 10694574 |
| touchdown enzyme time release-pcr for detection and identification of chlamydia trachomatis, c. pneumoniae, and c. psittaci using the 16s and 16s-23s spacer rrna genes. | three touchdown enzyme time release (tetr)-pcr assays were used to amplify different dna sequences in the variable regions of the 16s and 16s-23s spacer rrna genes specific for chlamydia trachomatis, chlamydia pneumoniae, and chlamydia psittaci as improved tests for sensitive diagnosis and rapid species differentiation. the tetr-pcr protocol used 60 cycles of amplification, which provided improved analytical sensitivity (0.004 to 0.063 inclusion-forming unit of chlamydia species per pcr). the se ... | 2000 | 10699002 |
| a simplified method for testing bordetella pertussis for resistance to erythromycin and other antimicrobial agents. | present methods of antimicrobial susceptibility testing of bordetella pertussis are time consuming and require specialized media that are not commercially available. we tested 52 isolates of b. pertussis for resistance to erythromycin, trimethoprim-sulfamethoxazole, chloramphenicol, and rifampin by agar dilution with bordet-gengou agar (bga) containing 20% horse blood (reference method), etest using bga and regan-lowe agar without cephalexin (rl-c), and disk diffusion using bga and rl-c. the org ... | 2000 | 10699011 |
| clinical validation of a polymerase chain reaction assay for the diagnosis of pertussis by comparison with serology, culture, and symptoms during a large pertussis vaccine efficacy trial. | to assess the diagnostic sensitivity and specificity of a bordetella pertussis polymerase chain reaction (pcr) assay using nasopharyngeal (np) specimens from subjects with cough illnesses participating in a large pertussis vaccine efficacy trial. | 2000 | 10699133 |
| adaptive responses of human monocytes infected by bordetella pertussis: the role of adenylate cyclase hemolysin. | the activation/adaptive responses of human monocytes exposed to bordetella pertussis parental or mutant strains were evaluated and correlated to the expression of two bacterial toxins: adenylate cyclase-hemolysin and pertussis toxin. the marked rise in intracellular cyclic adenosine monophosphate (camp) observed in monocytes infected by b. pertussis parental strain, inversely correlated with (1) the production of tumor necrosis factor alpha; (2) the release of superoxide anion; and (3) the expre ... | 2000 | 10699970 |
| the rcsab box. characterization of a new operator essential for the regulation of exopolysaccharide biosynthesis in enteric bacteria. | the interaction of the two transcriptional regulators rcsa and rcsb with a specific operator is a common mechanism in the activation of capsule biosynthesis in enteric bacteria. we describe rcsab binding sites in the wza promoter of the operon for colanic acid biosynthesis in escherichia coli k-12, in the galf promoter of the operon for k2 antigen biosynthesis in klebsiella pneumoniae, and in the tvia (vipr) promoter of the operon for vi antigen biosynthesis in salmonella typhi. we further show ... | 2000 | 10702265 |
| regulation of inflammatory responses to bordetella pertussis by n(g)-monomethyl-l-arginine in mice intranasally infected. | to investigate effect of mmla, an inhibitor of nitric oxide (no) production, on regulation of inflammatory responses to bordetella pertussis infection, mice were infected intranasally, and treated with various concentrations of mmla. ten days after infection, mice treated with mmla at dosage of 100 mg/kg, given intraperitoneally in a single dose or for 5 consecutive days, showed at histopathologic examination, a significant decrease of intensity of inflammation (scores, 0.6 +/- 0.2 and 0.9 +/- 0 ... | 1999 | 10704086 |
| microbial relatives of the seed storage proteins of higher plants: conservation of structure and diversification of function during evolution of the cupin superfamily. | this review summarizes the recent discovery of the cupin superfamily (from the latin term "cupa," a small barrel) of functionally diverse proteins that initially were limited to several higher plant proteins such as seed storage proteins, germin (an oxalate oxidase), germin-like proteins, and auxin-binding protein. knowledge of the three-dimensional structure of two vicilins, seed proteins with a characteristic beta-barrel core, led to the identification of a small number of conserved residues a ... | 2000 | 10704478 |
| aminoacyl-trna synthetases, the genetic code, and the evolutionary process. | the aminoacyl-trna synthetases (aarss) and their relationship to the genetic code are examined from the evolutionary perspective. despite a loose correlation between codon assignments and aars evolutionary relationships, the code is far too highly structured to have been ordered merely through the evolutionary wanderings of these enzymes. nevertheless, the aarss are very informative about the evolutionary process. examination of the phylogenetic trees for each of the aarss reveals the following. ... | 2000 | 10704480 |
| characterization of prostanoid receptors mediating inhibition of histamine release from anti-ige-activated rat peritoneal mast cells. | 1. prostanoid receptors mediating inhibition of anti-ige induced histamine release from rat peritoneal mast cells have been characterized pharmacologically. pgd2 and the specific dp receptor agonists bw 245c and zk 118182 were the most potent inhibitors with half-maximal concentrations of 0.26, 0.06 and 0.02 microm respectively. the maximum inhibition attainable was 60-65% with 10(-5) m bw 245c and zk 118182. 2. among several ep receptor agonists investigated, only pge2 and the ep2/ep3 receptor ... | 2000 | 10711359 |
| characterization of the uup locus and its role in transposon excisions and tandem repeat deletions in escherichia coli. | null mutations in the escherichia coli uup locus (at 21.8 min) serve to increase the frequency of reca-independent precise excision of transposable elements such as tn10 and to reduce the plaque size of bacteriophage mu (uup(-) phenotype). by the combined approaches of physical mapping of the mutations, complementation analyses, and protein overexpression from cloned gene fragments, we have demonstrated in this study that the uup(-) phenotype is the consequence of the absence of expression of th ... | 2000 | 10715006 |
| isolation and characterization of vich, encoding a new pleiotropic regulator in vibrio cholerae. | during the last decade, the hns gene and its product, the h-ns protein, have been extensively studied in escherichia coli. h-ns-like proteins seem to be widespread in gram-negative bacteria. however, unlike in e. coli and in salmonella enterica serovar typhimurium, little is known about their role in the physiology of those organisms. in this report, we describe the isolation of vich, an hns-like gene in vibrio cholerae, the etiological agent of cholera. this gene was isolated from a v. cholerae ... | 2000 | 10715012 |
| effect of pertussis toxin on the induction of nitric oxide synthesis in murine macrophages and on protection in vivo. | macrophages from mice immunised with whole cell pertussis vaccine (wcv) responded in vitro to selected antigens by nitric oxide (no) synthesis. this process was closely associated with macrophage activation. because of the postulated role of traces of pertussis toxin (pt) in the protective effects of wcv, native pt and a genetically detoxified pt (g-pt) in combination with either a heat-treated whole cell pertussis vaccine (dwcv) or a three component acellular vaccine (acv), were examined for th ... | 2000 | 10715525 |
| sequence-related protein export ntpases encoded by the conjugative transfer region of rp4 and by the cag pathogenicity island of helicobacter pylori share similar hexameric ring structures. | rp4 trbb, an essential component of the conjugative transfer apparatus of the broad-host-range plasmid rp4, is a member of the pule protein superfamily involved in multicomponent machineries transporting macromolecules across the bacterial envelope. pule-like proteins share several well conserved motifs, most notable a nucleoside triphosphate binding motif (p-loop). helicobacter pylori hp0525 also belongs to the pule superfamily and is encoded by the pathogenicity island cag, involved in the inf ... | 2000 | 10716714 |
| seroepidemiology of bordetella pertussis infections in the spanish population: a cross-sectional study. | a study was conducted on a representative sample (n=4084) of the spanish population to assess the prevalence of antibodies to pertussis toxin (pt) and filamentous hemagglutinin (fha). a total of 1982 men and 2102 women aged 5-59 years were stratified by sex and age (5-12, 13-19, 20-29, 30-39, 40-49 and 50-59 years). antibodies to pt were found in 46% samples and to fha in 74% and increased with age (p<0.0001), ranging from 35% in the 5-12 year age group to 52% in the 50-59 year age group for ant ... | 2000 | 10717335 |
| prolonged afebrile nonproductive cough illnesses in american soldiers in korea: a serological search for causation. | a serological study was undertaken to investigate infections in active-duty united states soldiers with illnesses characterized by prolonged, afebrile, nonproductive coughs. fifty-four soldiers were enrolled with such illness of >/=2 weeks' duration (case patients) along with 55 well soldiers (control subjects). serum samples were tested for igg and iga antibody to 3 bordetella pertussis antigens, pertussis agglutinins, igm antibodies to mycoplasma pneumoniae, igm and igg antibodies to chlamydia ... | 2000 | 10722440 |
| activation of intercellular adhesion molecule 1 expression by helicobacter pylori is regulated by nf-kappab in gastric epithelial cancer cells. | interactions between leukocytes and epithelial cells may play a key role in helicobacter pylori-associated gastric mucosal inflammation. this process is mediated by various cell adhesion molecules. the present study examined the molecular mechanisms leading to h. pylori-induced epithelial cell intercellular adhesion molecule-1 (icam-1; also called cd54) expression. coculture of epithelial cells with cytotoxin-associated gene pathogenicity island-positive (cag pai(+)) h. pylori strains, but not w ... | 2000 | 10722567 |
| bordetella pertussis tonb, a bvg-independent virulence determinant. | in gram-negative bacteria, high-affinity iron uptake requires the tonb/exbb/exbd envelope complex to release iron chelates from their specific outer membrane receptors into the periplasm. based on sequence similarities, the bordetella pertussis tonb exbb exbd locus was identified on a cloned dna fragment. the tight organization of the three genes suggests that they are cotranscribed. a putative fur-binding sequence located upstream from tonb was detected in a fur titration assay, indicating that ... | 2000 | 10722583 |
| role of adhesins and toxins in invasion of human tracheal epithelial cells by bordetella pertussis. | bordetella pertussis, the agent of whooping cough, can invade and survive in several types of eukaryotic cell, including cho, hela 229, and hep-2 cells and macrophages. in this study, we analyzed bacterial invasiveness in nonrespiratory human hela epithelial cells and human hte and hae0 tracheal epithelial cells. invasion assays and transmission electron microscopy analysis showed that b. pertussis strains invaded and survived, without multiplying, in hte or hae0 cells. this phenomenon was bvg r ... | 2000 | 10722585 |
| role of bordetella bronchiseptica fimbriae in tracheal colonization and development of a humoral immune response. | fimbriae are filamentous, cell surface structures which have been proposed to mediate attachment of bordetella species to respiratory epithelium. bordetella bronchiseptica has four known fimbrial genes: fim2, fim3, fimx, and fima. while these genes are unlinked on the chromosome, their protein products are assembled and secreted by a single apparatus encoded by the fimbcd locus. the fimbcd locus is embedded within the fha operon, whose genes encode another putative adhesin, filamentous hemagglut ... | 2000 | 10722598 |
| nonopsonic binding of type iii group b streptococci to human neutrophils induces interleukin-8 release mediated by the p38 mitogen-activated protein kinase pathway. | nonopsonic interaction of host immune cells with pathogens is an important first line of defense. we hypothesized that nonopsonic recognition between type iii group b streptococcus and human neutrophils would occur and that the interaction would be sufficient to trigger neutrophil activation. by using a serum-free system, it was found that heat-killed type iii group b streptococci bound to neutrophils in a rapid, stable, and inoculum-dependent manner that did not result in ingestion. transposon- ... | 2000 | 10722601 |
| molecular and biological analysis of eight genetic islands that distinguish neisseria meningitidis from the closely related pathogen neisseria gonorrhoeae. | the pathogenic species neisseria meningitidis and neisseria gonorrhoeae cause dramatically different diseases despite strong relatedness at the genetic and biochemical levels. n. meningitidis can cross the blood-brain barrier to cause meningitis and has a propensity for toxic septicemia unlike n. gonorrhoeae. we previously used subtractive hybridization to identify dna sequences which might encode functions specific to bacteremia and invasion of the meninges because they are specific to n. menin ... | 2000 | 10722605 |
| effect of chlamydia trachomatis infection and subsequent tumor necrosis factor alpha secretion on apoptosis in the murine genital tract. | the pathology observed during chlamydia infection is due initially to localized tissue damage caused by the infection itself, followed by deleterious host inflammatory responses that lead to permanent scarring. we have recently reported that the infection by chlamydia in vitro results in apoptosis of epithelial cells and macrophages and that infected monocytes secrete the proinflammatory cytokine interleukin-1beta. at the same time, proinflammatory cytokines such as tumor necrosis factor alpha ( ... | 2000 | 10722625 |
| bacterial exposure induces and activates matrilysin in mucosal epithelial cells. | matrilysin, a matrix metalloproteinase, is expressed and secreted lumenally by intact mucosal and glandular epithelia throughout the body, suggesting that its regulation and function are shared among tissues. because matrilysin is produced in paneth cells of the murine small intestine, where it participates in innate host defense by activation of prodefensins, we speculated that its expression would be influenced by bacterial exposure. indeed, acute infection (10-90 min) of human colon, bladder, ... | 2000 | 10725342 |
| folding of a synthetic parallel beta-roll protein. | recently, the design of beta-sheet proteins and concomitant folding studies have attracted increasing attention. a unique natural all-beta domain occurs in a family of cytolytic bacterial toxins, the so-called rtx toxins. this domain consists of a variable number (about 6-45) of tandem repeats of a glycine-rich nine-residue motif with the consensus sequence ggxgxdx(l/i/f)x. the analysis of the three-dimensional structure of alkaline protease from pseudomonas aeruginosa which possesses six of the ... | 2000 | 10734229 |
| ompr regulates the stationary-phase acid tolerance response of salmonella enterica serovar typhimurium. | tolerance to acidic environments is an important property of free-living and pathogenic enteric bacteria. salmonella enterica serovar typhimurium possesses two general forms of inducible acid tolerance. one is evident in exponentially growing cells exposed to a sudden acid shock. the other is induced when stationary-phase cells are subjected to a similar shock. these log-phase and stationary-phase acid tolerance responses (atrs) are distinct in that genes identified as participating in log-phase ... | 2000 | 10735868 |
| functional analysis of gapped microbial genomes: amino acid metabolism of thiobacillus ferrooxidans. | a gapped genome sequence of the biomining bacterium thiobacillus ferrooxidans strain atcc23270 was assembled from sheared dna fragments (3.2-times coverage) into 1,912 contigs. a total of 2,712 potential genes (orfs) were identified in 2.6 mbp (megabase pairs) of thiobacillus genomic sequence. of these genes, 2,159 could be assigned functions by using the wit-pro/emp genome analysis system, most with a high degree of certainty. nine hundred of the genes have been assigned roles in metabolic path ... | 2000 | 10737802 |
| bordetella pertussis infection: pathogenesis, diagnosis, management, and the role of protective immunity. | whooping cough is presently one of the ten most common causes of death from infectious disease worldwide. despite a high vaccine uptake, resurgences of this disease have been observed in several countries. virulence factors of bordetella pertussis include agglutinogens, fimbriae, p.69/pertactin, pertussis toxin, filamentous haemagglutinin, adenylate cyclase, tracheal cytotoxin, dermonecrotic toxin, lipopolysaccharide, tracheal colonisation factor, serum resistance factor, and type iii secretion. ... | 2000 | 10746492 |
| comparison of a commercial enzyme-linked immunosorbent assay with immunofluorescence and complement fixation tests for detection of coxiella burnetii (q fever) immunoglobulin m. | a commercially available enzyme-linked immunosorbent assay (elisa) for the diagnosis of q fever (panbio coxiella burnetii immunoglobulin m [igm] elisa, qfm-200) was compared to the indirect fluorescent antibody test (ifat) for c. burnetii igm and the complement fixation test (cft). the elisa demonstrated 92% agreement with the reference method (ifat), and gave a sensitivity of 99% (69 of 70 samples) and a specificity of 88% (106 of 121). specificity can be increased with confirmation by ifat. cf ... | 2000 | 10747159 |
| waning immunity and sub-clinical infection in an epidemic model: implications for pertussis in the netherlands. | in the netherlands, an epidemic outbreak of pertussis took place in 1996-1997. understanding of the causes of the epidemic is hampered by the fact that many cases of infection with bordetella pertussis go by unnoticed, and by the fact that immunity against infection does not last lifelong. motivated by these observations, we develop and analyze an age-structured epidemic model that takes these factors into account. a distinction is made between infection in immunologically naive individuals, and ... | 2000 | 10748285 |
| expression of functional influenza virus rna polymerase in the methylotrophic yeast pichia pastoris. | influenza virus rna polymerase with the subunit composition pb1-pb2-pa is a multifunctional enzyme with the activities of both synthesis and cleavage of rna and is involved in both transcription and replication of the viral genome. in order to produce large amounts of the functional viral rna polymerase sufficient for analysis of its structure-function relationships, the cdnas for rna segments 1, 2, and 3 of influenza virus a/pr/8, each under independent control of the alcohol oxidase gene promo ... | 2000 | 10756019 |
| genetic analysis of functions involved in adhesion of pseudomonas putida to seeds. | many agricultural uses of bacteria require the establishment of efficient bacterial populations in the rhizosphere, for which colonization of plant seeds often constitutes a critical first step. pseudomonas putida kt2440 is a strain that colonizes the rhizosphere of a number of agronomically important plants at high population densities. to identify the functions involved in initial seed colonization by p. putida kt2440, we subjected this strain to transposon mutagenesis and screened for mutants ... | 2000 | 10762233 |
| phosphorylation of hpr by the bifunctional hpr kinase/p-ser-hpr phosphatase from lactobacillus casei controls catabolite repression and inducer exclusion but not inducer expulsion. | we have cloned and sequenced the lactobacillus casei hprk gene encoding the bifunctional enzyme hpr kinase/p-ser-hpr phosphatase (hprk/p). purified recombinant l. casei hprk/p catalyzes the atp-dependent phosphorylation of hpr, a phosphocarrier protein of the phosphoenolpyruvate:carbohydrate phosphotransferase system at the regulatory ser-46 as well as the dephosphorylation of seryl-phosphorylated hpr (p-ser-hpr). the two opposing activities of hprk/p were regulated by fructose-1,6-bisphosphate, ... | 2000 | 10762262 |
| identification of a haemophilus influenzae 5'-nucleotidase protein: cloning of the nuca gene and immunogenicity and characterization of the nuca protein. | we report on the identification of a surface-exposed, highly conserved, immunogenic nontypeable haemophilus influenzae (nthi) protein, which elicits cross-reactive bactericidal antibodies against nthi. the protein was extracted from nthi strain p860295 with kscn and purified; it migrated as a single band on a sodium dodecyl sulfate-polyacrylamide gel with an apparent molecular mass of 63 kda. mouse antiserum generated against the purified protein was reactive on whole-cell enzyme-linked immunoso ... | 2000 | 10768940 |
| role of manganese-containing superoxide dismutase in oxidative stress and virulence of streptococcus pneumoniae. | streptococcus pneumoniae was shown to contain two types of superoxide dismutase, mnsod and fesod. levels of mnsod increased during growth in an aerobic environment. the soda gene, encoding mnsod, of virulent s. pneumoniae type 2 strain d39 was inactivated to give mutant d39hy1. aerobically, d39hy1 had a lower growth rate than the wild type and exhibited susceptibility to the redox-active compound paraquat, but anaerobic growth of d39hy1 was identical to that of the wild type. virulence studies s ... | 2000 | 10768978 |
| attenuation of and protection induced by a leucine auxotroph of mycobacterium tuberculosis. | attenuated mutants of mycobacterium tuberculosis represent potential vaccine candidates for the prevention of tuberculosis. it is known that auxotrophs of a variety of bacteria are attenuated in vivo and yet provide protection against challenge with wild-type organisms. a leucine auxotroph of m. tuberculosis was created by allelic exchange, replacing wild-type leud (rv2987c), encoding isopropyl malate isomerase, with a mutant copy of the gene in which 359 bp had been deleted, creating a strain r ... | 2000 | 10768986 |
| antibacterial agents and release of periplasmic pertussis toxin from bordetella pertussis. | pertussis toxin accumulates in the periplasm of bordetella pertussis prior to secretion, and we examined its fate following treatment with antimicrobial agents. both antibiotics that inhibit protein synthesis (erythromycin and chloramphenicol), transcription (rifampin), or cell wall biosynthesis (cefoperazone and piperacillin) and magnesium sulfate (which inhibits transcription of pertussis toxin, but not bacterial growth) did not prevent release of preformed toxin. in contrast, agents that affe ... | 2000 | 10770786 |
| [study of macrolide, lincosamide, and streptogramin b antibiotics resistance in staphylococcus aureus]. | macrolide antibiotics (mac) consist of a 12- to 16-membered lactone ring combined with a sugar moiety, and they inhibit protein synthesis via binding to 23s ribosomal rna in bacteria. the 14- and 16-membered mac are used for treating infectious diseases caused by gram-positive and other bacteria; e.g., haemophilus influenzae, bordetella pertussis, legionella pneumophila, campylobacter, treponema pallidum and mycoplasma. resistance to macrolide, lincosamide, and streptogramin-b (mls) antibiotics ... | 2000 | 10774259 |
| prenatal diagnosis of tracheal obstruction: possible association with maternal pertussis infection. | a fetus with the sonographic appearance of echogenic and enlarged lungs and dilated trachea and bronchi, indicating laryngotracheal obstruction, is reported. additionally, the fetus had ascites and subcutaneous edema and the amniotic fluid volume was reduced. doppler flow investigation of the systemic venous circulation revealed signs of heart failure, and color doppler visualized possible increased pulmonary flow. following termination of pregnancy, autopsy confirmed the sonographic observation ... | 2000 | 10776017 |
| mepyramine but not cimetidine or clobenpropit blocks pertussis toxin-induced histamine sensitization in rats. | the effects of pertussis toxin (pt) and the role of histaminergic h(1), h(2) and h(3) receptor blockade on the actions of histamine on blood pressure, heart rate, blood gas values, and mortality were studied in anaesthetized rats. four days after treatment with pt, histamine dose-dependently decreased mean arterial blood pressure (map) and pt enhanced the histamine-induced decrease in map. in the pt but not in the inactivated pt (ipt) or saline treated group three out of six animals died after t ... | 2000 | 10780989 |
| enzymology of type iv macromolecule secretion systems: the conjugative transfer regions of plasmids rp4 and r388 and the cag pathogenicity island of helicobacter pylori encode structurally and functionally related nucleoside triphosphate hydrolases. | type iv secretion systems direct transport of protein or nucleoprotein complexes across the cell envelopes of prokaryotic donor and eukaryotic or prokaryotic recipient cells. the process is mediated by a membrane-spanning multiprotein assembly. potential ntpases belonging to the virb11 family are an essential part of the membrane-spanning complex. three representatives of these ntpases originating from the conjugative transfer regions of plasmids rp4 (trbb) and r388 (trwd) and from the cag patho ... | 2000 | 10781544 |
| the arcb sensor kinase of escherichia coli: genetic exploration of the transmembrane region. | the arc two-component signal transduction system of escherichia coli regulates the expression of numerous operons in response to respiratory growth conditions. cellular redox state or proton motive force (delta(h(+))) has been proposed to be the signal for the membrane-associated arcb sensor kinase. this study provided evidence for a short arcb periplasmic bridge that contains a his47. the dispensability of this amino acid, the only amino acid with a pk in the physiological range, renders the de ... | 2000 | 10781568 |
| hospitalization and complications in children under 2 years of age with bordetella pertussis infection. | we prospectively followed 725 children under 2 years of age with laboratory-diagnosed bordetella pertussis infection to investigate the hospitalization rate and complications. diagnosis was made by culture and polymerase chain reaction (pcr) from nasopharyngeal swabs in 11,016 children who presented with > or = 7 days of cough at 63 pediatric practices in germany. of these children, 33 (4.5%) were hospitalized at a mean age of 4.8 months (range, 17 days to 19.5 months). complications occurred in ... | 2000 | 10782397 |
| adult formulation of a five component acellular pertussis vaccine combined with diphtheria and tetanus toxoids and inactivated poliovirus vaccine is safe and immunogenic in adolescents and adults. | pertussis is increasingly recognized as an important cause of cough illness in adolescents and adults. | 2000 | 10783014 |
| novel genes involved in the regulation of pathogenicity factor production within the rpf gene cluster of xanthomonas campestris. | the synthesis of extracellular enzymes and extracellular polysaccharide (eps) in xanthomonas campestris pathovar campestris (xcc) is subject to co-ordinate regulation by a cluster of genes called rpf (for regulation of pathogenicity factors). these genes are located within a 21.9 kb region of the chromosome isolated as the cosmid clone pij3020. the genes in the left-hand section of this region of the chromosome have previously been characterized. this paper reports on the genes in the right-hand ... | 2000 | 10784047 |
| modulating phagocyte activation: the pros and cons of helicobacter pylori virulence factors. | | 2000 | 10790419 |
| the neutrophil-activating protein (hp-nap) of helicobacter pylori is a protective antigen and a major virulence factor. | helicobacter pylori infection induces the appearance of inflammatory infiltrates, consisting mainly of neutrophils and monocytes, in the human gastric mucosa. a bacterial protein with neutrophil activating activity (hp-nap) has been previously identified, but its role in infection and immune response is still largely unknown. here, we show that vaccination of mice with hp-nap induces protection against h. pylori challenge, and that the majority of infected patients produce antibodies specific fo ... | 2000 | 10790422 |
| primary role for gi protein signaling in the regulation of interleukin 12 production and the induction of t helper cell type 1 responses. | we explored the role of gi protein signaling in the regulation of interleukin (il)-12 production and t helper cell type 1 (th1) t cell differentiation. in initial studies, we showed that treatment of normal mice with pertussis toxin (pt), which inhibits gi protein signaling, enhanced the capacity of splenocytes to produce il-12 in response to both microbial and nonmicrobial stimuli. in addition, pt treatment increased the production of tumor necrosis factor (tnf)-alpha and il-10 by stimulated ce ... | 2000 | 10790434 |
| binding of murine antibodies against whole-cell pertussis vaccine or filamentous haemagglutinin by bordetella pertussis from patients with whooping cough. | in 1996 an unexpected rise in the incidence of whooping cough occurred in the netherlands, and antigenic divergence between vaccine strains and clinical isolates has been suggested as a cause for this phenomenon. to investigate this assumption, the binding of murine antibodies against the whole-cell pertussis vaccine or filamentous haemagglutinin, an important protective antigen, to a limited number of bordetella pertussis strains isolated during different time-periods (1991-92, 1994 and 1996) w ... | 2000 | 10792847 |
| detection of bordetella pertussis in a clinical laboratory by culture, polymerase chain reaction, and direct fluorescent antibody staining; accuracy, and cost. | control of bordetella pertussis in the community is hampered by slow and insensitive diagnostic tests. we therefore examined the accuracy and cost of culture, direct fluorescent antibody (dfa) staining, and pcr in a routine clinical laboratory. six hundred thirty seven nasopharyngeal swabs and aspirates in casamino acids transport medium were cultured, stained with polyclonal (difco), and monoclonal (bl-5 and accu-mab) anti-b. pertussis reagents, and amplified by an is481-specific pcr. pcr produ ... | 2000 | 10794935 |
| epidemiological typing of bordetella pertussis isolates: recommendations for a standard methodology. | pertussis is re-emerging in vaccinated populations, and to gain insight into the reasons for this development population-based studies are necessary. unfortunately, various techniques are used to study bordetella pertussis populations, hampering comparison between studies. a standard methodology for epidemiological typing of bordetella pertussis isolates is proposed which is based on serotyping, pulsed-field gel electrophoresis and gene typing. such a standard approach will allow comparisons bet ... | 2000 | 10795589 |
| acellular vaccines for preventing whooping cough in children. | routine use of whole cell pertussis vaccines was suspended in some countries in the late 1970s and early 1980s, leading to a resurgence of whooping cough. acellular pertussis vaccines containing purified or recombinant bordetella pertussis antigens were developed in the hope that they would be as effective but less toxic than the whole cell vaccines. the objective of this review was to assess the effects of acellular pertussis vaccines in children. | 2000 | 10796648 |
| comparison of five commercial enzyme-linked immunosorbent assays for detection of antibodies to bordetella pertussis. | measuring antibodies to bordetella pertussis antigens is mostly done by enzyme-linked immunosorbent assays (elisas). we compared the performance of five commercially available elisa kits with the help of 65 serum specimens which were repetitively tested for evaluation of the kits. the specimens contained 20 paired serum samples from patients with clinical pertussis, 15 samples were from children vaccinated with a diphtheria-tetanus-acellular pertussis vaccine, seven specimens were taken from an ... | 2000 | 10799456 |
| [humoral reaction to bordetella pertussis antigens: pertussis toxin, filamentous hemagglutinin and lipopolysaccharide in children with clinical symptoms of whooping cough. i. antibody level for b pertussis antigens in children without respiratory tract infection symptoms]. | the aim of the first part of this study was to determine antibody level to pertussis toxin, filamentous hemagglutinin and endotoxin of b. pertussis in children without symptoms of respiratory tract infection. the serum samples obtained from 276 children (age range: 6 weeks-16 years) were examined using indirect hemagglutination and elisa tests. normal antibody levels to 3 b. pertussis antigens were determined for 95% of the serum samples as the upper cut-off levels depending on children age. ver ... | 1999 | 10803255 |
| [humoral reaction to bordetella pertussis antigens: pertussis toxin, filamentous hemagglutinin and lipopolysaccharide in children with clinical symptoms of whooping cough. ii. occurence and level of b. pertussis antigens in children with suspected whooping cough]. | the aim of this study was to determine and evaluate igg, igm and iga levels to pertussis toxin (pt), filamentous hemagglutinin (fha) and endotoxin (lps) of b. pertussis in children with clinical symptoms of whooping cough. the serum samples obtained from 265 children (age range: 2 months-16 years) suspected of pertussis were examined by indirect haemagglutination (ih) and elisa tests. higher antibody level was most frequently observed in iga class to pt, fha and lps in 45.3%, 35.1% and 66% of pe ... | 1999 | 10803256 |
| seroprevalence of pertussis antibodies among adolescents in israel. | there is an increasing number of reports of pertussis among older children and adults. the development and licensure of an acellular pertussis vaccine offer the possibility of adult vaccination against the disease. information on immunity to pertussis in this age group is needed before any vaccination policy can be considered. | 2000 | 10804947 |
| yersinia enterocolitica tyea, an intracellular regulator of the type iii machinery, is required for specific targeting of yope, yoph, yopm, and yopn into the cytosol of eukaryotic cells. | pathogenic yersinia species employ type iii machines to target effector yops into the cytosol of eukaryotic cells. yersinia tyea mutants are thought to be defective in the targeting of yope and yoph without affecting the injection of yopm, yopn, yopo, yopp, and yopt into the cytosol of eukaryotic cells. one model suggests that tyea may form a tether between yopn (lcre) and yopd on the bacterial surface, a structure that may translocate yope and yoph across the plasma membrane of eukaryotic cells ... | 2000 | 10809698 |
| human nerve growth factor protects common marmosets against autoimmune encephalomyelitis by switching the balance of t helper cell type 1 and 2 cytokines within the central nervous system. | multiple sclerosis is a demyelinating disorder of the central nervous system (cns), in which an immune attack directed against myelin constituents causes myelin destruction and death of oligodendrocytes, the myelin-producing cells. here, the efficacy of nerve growth factor (ngf), a growth factor for neurons and oligodendrocytes, in promoting myelin repair was evaluated using the demyelinating model of experimental allergic encephalomyelitis (eae) in the common marmoset. surprisingly, we found th ... | 2000 | 10811872 |
| characterization of murine coronavirus neutralization epitopes with phage-displayed peptides. | phage-displayed peptide libraries were used to map immunologically relevant epitopes on the surface (s) glycoprotein of a neurotropic murine coronavirus (mhv-a59). three in vitro virus-neutralizing and in vivo protective mabs against either continuous or discontinuous epitopes on the s glycoprotein were used to screen 12 different peptide libraries expressed on the pviii major coat protein of the fd filamentous bacteriophage. consensus sequences that matched short sequences within the s glycopro ... | 2000 | 10814583 |
| characterization of fimy as a coactivator of type 1 fimbrial expression in salmonella enterica serovar typhimurium. | type 1 fimbriae of salmonella enterica serovar typhimurium are surface appendages that carry adhesins specific for mannosylated host glycoconjugates. regulation of the major fimbrial subunit is thought to be controlled by a number of ancillary fim genes, including fimz, fimy, fimw, and fimu. previous studies using a fimz mutant have indicated that this protein is necessary for fima expression, and in vitro dna binding assays determined that fimz is a transcriptional activator that binds directly ... | 2000 | 10816478 |
| identification of a human lactoferrin-binding protein in gardnerella vaginalis. | previous studies have shown that gardnerella vaginalis can utilize iron-loaded human lactoferrin as a sole source of iron. in this study, g. vaginalis cells were shown to bind digoxigenin (dig)-labeled human lactoferrin in a dot blot assay. using the dig-labeled human lactoferrin, a 120-kda human lactoferrin-binding protein was detected by western blot analysis of g. vaginalis proteins. the lactoferrin-binding activity of this protein was found to be heat stable. competition studies indicated th ... | 2000 | 10816496 |
| characterization of hemolysin of moraxella bovis using a hemolysis-neutralizing monoclonal antibody. | a concentrated bacterial culture supernatant from the hemolytic moraxella bovis strain uqv 148nf was used to immunize mice and generate monoclonal antibodies (mabs). one, mab g3/d7, neutralized the hemolytic activity of m. bovis and recognized a 94-kda protein by western blot analysis in hemolytic m. bovis strains representing each of the different fimbrial serogroups. exposure of corneal epithelial cells to m. bovis concentrated culture supernatants demonstrated a role for an exotoxin in the pa ... | 2000 | 10816500 |
| stimulation of bordetella pertussis adenylate cyclase toxin intoxication by its hemolysin domain. | the internalization of the n-terminal catalytic domain of bordetella pertussis adenylate cyclase toxin (act) across the cytoplasmic membrane has been considered to occur independently from protein-protein interactions which can lead to oligomerization required for hemolytic activity by its c-terminal hemolysin domain. here we report that when added in excess, this hemolysin domain stimulates the internalization, suggesting the involvement of protein-protein interactions in cell-invasive activity ... | 2000 | 10816536 |
| constitutive mutations of the salmonella enterica serovar typhimurium transcriptional virulence regulator phop. | the phop-phoq two-component system is necessary for the virulence of salmonella spp. and is responsible for regulating several modifications of the lipopolysaccharide (lps). mutagenesis of the transcriptional regulator phop resulted in the identification of a mutant able to activate transcription of regulated genes approximately 100-fold in the absence of phoq. sequence analysis showed two single-base alterations resulting in amino acid changes at positions 93 (s93n) and 203 (q203r). these mutat ... | 2000 | 10816543 |
| use of pertussis toxin encoded by ptx genes from bordetella bronchiseptica to model the effects of antigenic drift of pertussis toxin on antibody neutralization. | recently, concern has been voiced about the potential effect that antigenic divergence of circulating strains of bordetella pertussis might have on the efficacy of pertussis vaccines. in order to model antigenic drift of pertussis toxin, a critical component of many pertussis vaccines, and to examine the effects of such drift on antibody neutralization, we engineered a strain of b. pertussis to produce a variant pertussis toxin molecule that contains many of the amino acid changes found in the t ... | 2000 | 10816544 |
| experimental allergic conjunctivitis in guinea pigs induced by japanese cedar pollen. | we report a new experimental allergic conjunctivitis with japanese cedar pollen as antigen in guinea pigs, and the immunological characteristics of this model were also elucidated. allergic conjunctivitis was developed by immunization in guinea pigs with a mixture containing japanese cedar pollen and killed bordetella pertussis. when local application of japanese cedar pollen suspension 14 d after systemic immunization was performed every 3d, remarkable conjunctivitis was observed from 20 to 35 ... | 2000 | 10823665 |
| in vitro activity of gemifloxacin and other antimicrobial agents against isolates of bordetella pertussis and bordetella parapertussis. | we investigated the activity of the novel quinolone agent gemifloxacin (sb-265805) and a panel of comparator agents against bordetella pertussis and bordetella parapertussis. erythromycin, azithromycin, ciprofloxacin and gemifloxacin were consistently active against both species. an azithromycin- and erythromycin-resistant b. pertussis isolate was not resistant to any of the other agents tested (gemifloxacin mic < or =0.008 mg/l; ciprofloxacin, 0.015 mg/l; ampicillin, 2.0 mg/l; trimethoprim-sulp ... | 2000 | 10824032 |
| dimerization of signalling modules of the evgas and bvgas phosphorelay systems. | biophysical and biochemical properties of signalling proteins or domains derived from the unorthodox evgas and bvgas two-component phosphorelay systems of escherichia coli and bordetella pertussis were investigated. oligomerization of the effector proteins evga and bvga and of truncated evgs and bvgs derived signalling proteins containing the receiver and histidine containing phosphotransfer (hpt) domains or comprising only the hpt domains were characterized by native gel electrophoresis, gel pe ... | 2000 | 10825546 |
| molecular characterization of bordetella bronchiseptica filamentous haemagglutinin and its secretion machinery. | two closely related pathogens, bordetella pertussis and bordetella bronchiseptica, share a number of virulence factors. filamentous haemagglutinin (fha) is widely regarded as the dominant adhesin of b. pertussis, and its multiple binding activities have been well characterized. this large protein is produced and secreted at high levels by b. pertussis and significantly lower levels by b. bronchiseptica strains. fha secretion is mediated by a single outer-membrane accessory protein, fhac. the gen ... | 2000 | 10832649 |
| recovery of bordetella holmesii from patients with pertussis-like symptoms: use of pulsed-field gel electrophoresis to characterize circulating strains. | a 4-year retrospective study showing that we isolated bordetella holmesii, but not bordetella pertussis, from patients with pertussis-like symptoms was performed. from 1995 through 1998, we isolated b. holmesii from 32 nasopharyngeal specimens that had been submitted from patients suspected of having pertussis. previously, b. holmesii had been associated mainly with septicemia and was not thought to be associated with respiratory illness. a study was undertaken to describe the characteristics of ... | 2000 | 10834997 |
| g protein-mediated fmrfamidergic modulation of calcium influx in dissociated heart muscle cells from squid, loligo forbesii. | the actions of the neuropeptide fmrfamide (phe-met-arg-phe-nh2) on the l-type (ica,l) and t-type (ica,t) calcium currents were investigated in muscle cells dissociated from the heart of squid, loligo forbseii. the heart muscle cells could be divided into type i and type ii cells, on the basis of morphological differences in the dissociated myocytes. fmrfamide induced a substantial block of the l-type calcium current seen in type i cells; this inhibition was rapid, reversible and dose dependent ( ... | 2000 | 10835048 |
| cell-mediated immunity and antibody responses to bordetella pertussis antigens in children with a history of pertussis infection and in recipients of an acellular pertussis vaccine. | cell-mediated immunity (cmi) and antibody responses to bordetella pertussis antigens were assessed 4-6 years after primary infant immunization with diphtheria-tetanus tricomponent acellular pertussis (dtap) or diphtheria-tetanus (dt) vaccine in a country with high endemicity of b. pertussis infection. cmi to the b. pertussis antigens (especially to the pertussis toxin [pt]) was more frequent and/or intense in dtap than in dt recipients. no lymphoproliferation differences were found between those ... | 2000 | 10837180 |
| protection against bordetella pertussis in mice in the absence of detectable circulating antibody: implications for long-term immunity in children. | most vaccines used for humans work through humoral immunity, yet many appear to be protective even after specific circulating antibody levels have waned to undetectable levels. furthermore, it has been difficult to define a serologic correlate of protection against a number of infectious diseases, including those caused by bordetella pertussis. b. pertussis clearance in immunized mice has been shown to correlate with pertussis vaccine efficacy in children. this murine respiratory challenge model ... | 2000 | 10837200 |
| protective immunity to bordetella pertussis requires both b cells and cd4(+) t cells for key functions other than specific antibody production. | to investigate the fundamental nature of protective immunity to bordetella pertussis, we studied intranasal immunization of adult mice with formalin-fixed b. pertussis (ffbp), followed by aerosol b. pertussis challenge. mice given two doses of ffbp intranasally completely cleared a subsequent pertussis aerosol challenge from tracheae and lungs (defined as protection), but there was no correlation between levels of specific antibody and clearance of bacteria. further, transfer of immune serum bef ... | 2000 | 10839801 |
| in vivo induction of a high-avidity, high-frequency cytotoxic t-lymphocyte response is associated with antiviral protective immunity. | many approaches are currently being developed to deliver exogenous antigen into the major histocompatibility complex class i-restricted antigen pathway, leading to in vivo priming of cd8(+) cytotoxic t cells. one attractive possibility consists of targeting the antigen to phagocytic or macropinocytic antigen-presenting cells. in this study, we demonstrate that strong cd8(+) class i-restricted cytotoxic responses are induced upon intraperitoneal immunization of mice with different peptides, chara ... | 2000 | 10846055 |
| human parechovirus 1 utilizes integrins alphavbeta3 and alphavbeta1 as receptors. | human parechovirus 1 (hpev1) displays an arginine-glycine-aspartic acid (rgd) motif in the vp1 capsid protein, suggesting integrins as candidate receptors for hpev1. a panel of monoclonal antibodies (mabs) specific for integrins alphavbeta3, alphavbeta1, and alphavbeta5, which have the ability to recognize the rgd motif, and also a mab specific for integrin alpha2beta1, an integrin that does not recognize the rgd motif, were tested on a549 cells. our results showed that integrin alphav-specific ... | 2000 | 10846065 |
| characterization of a bordetella pertussis diaminopimelate (dap) biosynthesis locus identifies dapc, a novel gene coding for an n-succinyl-l,l-dap aminotransferase. | the functional complementation of two escherichia coli strains defective in the succinylase pathway of meso-diaminopimelate (meso-dap) biosynthesis with a bordetella pertussis gene library resulted in the isolation of a putative dap operon containing three open reading frames (orfs). in line with the successful complementation of the e. coli dapd and dape mutants, the deduced amino acid sequences of two orfs revealed significant sequence similarities with the dapd and dape proteins of e. coli an ... | 2000 | 10850974 |
| phosphorelay as the sole physiological route of signal transmission by the arc two-component system of escherichia coli. | the arc two-component system, comprising a tripartite sensor kinase (arcb) and a response regulator (arca), modulates the expression of numerous genes involved in respiratory functions. in this study, the steps of phosphoryl group transfer from phosphorylated arcb to arca were examined in vivo by using single copies of wild-type and mutant arcb alleles. the results indicate that the signal transmission occurs solely by his-asp-his-asp phosphorelay. | 2000 | 10851007 |
| [the development of a process for culturing bordetella pertussis immobilized on a polyurethane carrier]. | the processes of the cultivation of bordetella pertussis, immobilized on polyurethane carrier in a fermenter, were carried out and studied. acellular pertussis preparations were produced from the culture fluid obtained in the batch and multi-cycle cultivation processes with immobilized cells, as well as in the process with interrupted fermentation (for confirming the possibility of the preservation of cell viability). the content of protein and b. pertussis toxin in these preparations, as well a ... | 1999 | 10851980 |
| point mutations in a peptidoglycan biosynthesis gene cause competence induction in haemophilus influenzae. | we have identified three new haemophilus influenzae mutations causing cells to exhibit extreme hypercompetence at all stages of growth. the mutations are in mure, which encodes the meso-diaminopimelate-adding enzyme of peptidoglycan synthesis. all are point mutations causing nonconservative amino acid substitutions, two at a poorly conserved residue (g(435)-->r and g(435)-->w) and the third at a highly conserved leucine (l(361)-->s). the mutant strains have very similar phenotypes and do not exh ... | 2000 | 10852860 |
| salmonella enterica serovar typhimurium peptidase b is a leucyl aminopeptidase with specificity for acidic amino acids. | peptidase b (pepb) of salmonella enterica serovar typhimurium is one of three broad-specificity aminopeptidases found in this organism. we have sequenced the pepb gene and found that it encodes a 427-amino-acid (46.36-kda) protein, which can be unambiguously assigned to the leucyl aminopeptidase (lap) structural family. pepb has been overexpressed and purified. the active enzyme shows many similarities to other members of the lap family: it is a heat-stable (70 degrees c; 20 min) hexameric ( app ... | 2000 | 10852868 |
| the n- and c-terminal portions of the agrobacterium virb1 protein independently enhance tumorigenesis. | genetic transformation of plants by agrobacterium tumefaciens is mediated by a virulence (vir)-specific type iv secretion apparatus assembled from 11 virb proteins and vird4. virb1, targeted to the periplasm by an n-terminal signal peptide, is processed to yield virb1*, comprising the c-terminal 73 amino acids. the n-terminal segment, which shares homology with chicken egg white lysozyme as well as lytic transglycosylases, may provide local lysis of the peptidoglycan cell wall to create channels ... | 2000 | 10852875 |
| the brucella abortus ccrm dna methyltransferase is essential for viability, and its overexpression attenuates intracellular replication in murine macrophages. | the ccrm dna methyltransferase of the alpha-proteobacteria catalyzes the methylation of the adenine in the sequence gantc. like dam in the enterobacteria, ccrm plays a regulatory role in caulobacter crescentus and rhizobium meliloti. ccrm is essential for viability in both of these organisms, and we show here that it is also essential in brucella abortus. further, increased copy number of the ccrm gene results in striking changes in b. abortus morphology, dna replication, and growth in murine ma ... | 2000 | 10852881 |
| isolation and characterization of nonchemotactic chez mutants of escherichia coli. | the escherichia coli chez protein stimulates dephosphorylation of chey, a response regulator in the chemotaxis signal transduction pathway, by an unknown mechanism. genetic analysis of chez has lagged behind biochemical and biophysical characterization. to identify putative regions of functional importance in chez, we subjected chez to random mutagenesis and isolated 107 nonchemotactic chez mutants. missense mutations clustered in six regions of chez, whereas nonsense and frameshift mutations we ... | 2000 | 10852888 |
| transferred dna (t-dna)-associated proteins of agrobacterium tumefaciens are exported independently of virb. | the transfer of t-dna from agrobacterium to plant cells is mediated by a system which involves the virb operon of the ti plasmid. we report that vire2 and vird2, two t-dna-associated proteins, as well as virf, a protein known to be secreted into plant cells, are present in the periplasm and supernatant fractions of growing cells of agrobacterium as are virj and chve, two known periplasmic proteins. two cytoplasmic proteins, ros and chloramphenicol acetyl transferase, and a vire2green fluorescent ... | 2000 | 10852952 |