Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| identification, characterization, and variation in expression of two serologically distinct o-antigen epitopes in lipopolysaccharides of campylobacter fetus serotype a strains. | monoclonal antibodies (mabs) to the lipopolysaccharide (lps) o-antigens of campylobacter fetus serotype a and b strains were produced. eight mabs specific for serotype a lps were characterized on immunoblots of c. fetus serotype a lps. two immunoblot patterns were observed and were used to divide the eight mabs into two groups. mabs m1177 and m1194 were selected as representative of the two groups and were used in an enzyme-linked immunosorbent assay (elisa) to examine the lps o-antigen epitopes ... | 2001 | 11705938 |
| pertussis toxin and lipopolysaccharide influence phagocytosis of bordetella pertussis by human monocytes. | the potential of human monocytes to mediate the clearance of bordetella pertussis infection was examined. bacteria expressing green fluorescent protein were incubated with adherent peripheral blood monocytes, and phagocytosis was quantified by using fluorescence microscopy. monocytes internalized only a small percentage of the adherent bacteria. surface-associated bvg-regulated virulence factors, including adenylate cyclase toxin and filamentous hemagglutinin, did not affect attachment or phagoc ... | 2001 | 11705943 |
| immune response genes modulate serologic responses to vibrio cholerae tcpa pilin peptides. | cholera is an enteric disease caused by vibrio cholerae. toxin-coregulated pilus (tcp), a type 4 pilus expressed by v. cholerae, is a cholera virulence factor that is required for host colonization. the tcp polymer is composed of subunits of tcpa pilin. antibodies directed against tcpa are protective in animal models of cholera. while natural or recombinant forms of tcpa are difficult to purify to homogeneity, it is anticipated that synthesized tcpa peptides might serve as immunogens in a subuni ... | 2001 | 11705949 |
| antimicrobial susceptibility testing of clinical isolates of bordetella pertussis from northern california: report from the sentry antimicrobial surveillance program. | reports of an increased clinical incidence of pertussis and the development of resistance by bordetella pertussis to erythromycin prompted the collection and testing of recent clinical isolates from patients in northern california against a range of antimicrobial agents by the etest (ab biodisk, solna, sweden) method. all isolates were fully susceptible to all eight agents tested (mic, <or=0.38 microg/ml), including newer fluoroquinolones, such as gatifloxacin (mic of which 90% of the isolates t ... | 2001 | 11709347 |
| fimbrial typing of bordetella pertussis isolates: agglutination with polyclonal and monoclonal antibodies. | 2001 | 11712516 | |
| fc receptor-mediated immunity against bordetella pertussis. | the relevance of specific abs for the induction of cellular effector functions against bordetella pertussis was studied. igg-opsonized b. pertussis was efficiently phagocytosed by human polymorphonuclear leukocytes (pmn). this process was mediated by the pmn igg receptors, fcgammariia (cd32) and fcgammariiib (cd16), working synergistically. furthermore, these fcgammar triggered efficient pmn respiratory burst activity and mediated transfer of b. pertussis to lysosomal compartments, ultimately re ... | 2001 | 11714823 |
| redox signal transduction by the arcb sensor kinase of haemophilus influenzae lacking the pas domain. | the arc (anoxic redox control) two-component signal transduction system of escherichia coli, which comprises the tripartite arcb sensor kinase and the arca response regulator, modulates the expression of numerous operons in response to redox conditions of growth. we demonstrate that the arca and arcb genes of haemophilus influenzae specify a two-component system. the arc proteins of the two bacterial species sufficiently resemble each other that they can participate in heterologous transphosphor ... | 2001 | 11717280 |
| polymorphism of bordetella pertussis isolates circulating for the last 10 years in france, where a single effective whole-cell vaccine has been used for more than 30 years. | we compared bordetella pertussis isolates collected in france over the last 10 years, the vaccine strains used for more than 30 years, and isolates collected before the introduction of generalized vaccination. the analysis included serotyping, pulsed-field gel electrophoresis of chromosomal dna after digestion with xbai and spei, and sequencing of the pt s1 gene, encoding the s1 subunit of pertussis toxin, and the prn gene, encoding the adhesin pertactin. we found that the incidence of infection ... | 2001 | 11724851 |
| construction of mini-tn5cyaa' and its utilization for the identification of genes encoding surface-exposed and secreted proteins in bordetella bronchiseptica. | a mini-tn5 transposon derivative, mini-tn5cyaa', has been constructed. it contains a promoter-less and ribosome binding site-deficient reporter gene, encoding the catalytic domain of bordetella pertussis adenylate cyclase toxin (cyaa'). we used this system to mutagenize b. bronchiseptica and we developed a screen for identification of mutants containing cyaa' translational fusions. this system was used to identify b. bronchiseptica genes that encode surface-exposed and secreted proteins. | 2001 | 11728725 |
| immunologic and epidemiologic experience of vaccination with a monocomponent pertussis toxoid vaccine. | pertussis re-emerged in sweden with a cumulative incidence of about 60% during the first 10 years of life, when the locally produced cellular vaccine lost its efficacy around 1970 and general vaccination was discontinued in 1979. the epidemiology, clinical features, and immunology of pertussis and a monocomponent pertussis toxoid vaccine were studied in göteborg, sweden. after phase 1 and 2 studies, a randomized, double-blind, placebo-controlled trial of pertussis toxoid (ptox), compounded with ... | 2001 | 11731642 |
| proliferating macrophages, dendritic cells, natural killer cells, t and b lymphocytes in the middle ear and eustachian tube mucosa during experimental acute otitis media in the rat. | although many studies focus on the increase of immunocompetent cells within the middle ear mucosa during acute otitis media it is poorly understood how this increase is mediated. the differentiation between two possible causes, i.e. immigration and local proliferation, would help to better understand the pathophysiology of this disease. therefore, the number of proliferating macrophages, dendritic cells, natural killer cells and t and b lymphocytes was studied during acute otitis media in the ra ... | 2001 | 11737056 |
| tetanus toxin fragment c-specific priming by intranasal infection with recombinant bordetella pertussis. | as an alternative to parenteral administration, mucosal administration offers several advantages including the ease of administration, safety and the ability to induce mucosal immunity. as a first step towards nasal administration of important childhood vaccines, we have previously developed attenuated bordetella pertussis strains able to protect mice against pertussis upon nasal vaccination. since pertussis vaccines are generally combined with tetanus and diphtheria vaccines, we constructed rec ... | 2001 | 11738759 |
| efficacy and safety of clarithromycin versus erythromycin for the treatment of pertussis: a prospective, randomized, single blind trial. | pertussis is still a prevalent public health problem, and antibiotic therapy may decrease disease severity and limit communicability. erythromycin is the recommended antibiotic for treatment and prophylaxis of pertussis; however, side effects of erythromycin limit its usefulness in some patients. clarithromycin, a newer macrolide, has good in vitro activity against bordetella pertussis and a better side effect profile. | 2001 | 11740322 |
| inhibitory effect on immunoglobulin e production in vivo and in vitro by siegesbeckia glabrescens. | elevated levels of immunoglobulin (ig)e are associated with immediate-type allergic reactions. the effect of an aqueous extract of siegesbeckia glabrescens (compositae) whole plants (sgwp) on in vivo and in vitro ige production was studied in mice. sgwp dose-dependently inhibited the active systemic anaphylaxis and serum ige production induced by immunization with ovalbumin and bordetella pertussis toxin absorbed to aluminium hydroxide gel. sgwp dose-dependently inhibited il-4-dependent ige prod ... | 2001 | 11746835 |
| rapid identification of bordetella pertussis pertactin gene variants using lightcycler real-time polymerase chain reaction combined with melting curve analysis and gel electrophoresis. | recently, eight allelic variants of the pertactin gene (prn1-8) have been characterized in bordetella pertussis strains isolated in europe and the united states. it has been suggested that the divergence of the pertactin types of clinical isolates from those of the b. pertussis vaccine strains is a result of vaccine-driven evolution. sequencing of the prn, which is relatively time-consuming, has so far been the only method for the differentiation of prn types. we have developed a rapid real-time ... | 2001 | 11747721 |
| binding of c4b-binding protein to porin: a molecular mechanism of serum resistance of neisseria gonorrhoeae. | we screened 29 strains of neisseria gonorrhoeae and found 16/21 strains that resisted killing by normal human serum and 0/8 serum sensitive strains that bound the complement regulator, c4b-binding protein (c4bp). microbial surface-bound c4bp demonstrated cofactor activity. we constructed gonococcal strains with hybrid porin (por) molecules derived from each of the major serogroups (por1a and por1b) of n. gonorrhoeae, and showed that the loop 1 of por1a is required for c4bp binding. por1b loops 5 ... | 2001 | 11157049 |
| subset of hybrid eukaryotic proteins is exported by the type i secretion system of erwinia chrysanthemi. | erwinia chrysanthemi exports degradative enzymes by using a type i protein secretion system. the proteases secreted by this system lack an n-terminal signal peptide but contain a c-terminal secretion signal. to explore the substrate specificity of this system, we have expressed the e. chrysanthemi transporter system (prtdef genes) in escherichia coli and tested the ability of this abc transporter to export hybrid proteins carrying c-terminal fragments of e. chrysanthemi protease b. the c terminu ... | 2001 | 11157948 |
| sige is a chaperone for the salmonella enterica serovar typhimurium invasion protein sigd. | sigd is translocated into eucaryotic cells by a type iii secretion system. in this work, evidence that the putative chaperone sige directly interacts with sigd is presented. a bacterial two-hybrid system demonstrated that sige can interact with itself and sigd. in addition, sigd was specifically copurified with sige-his(6) on a nickel column. | 2001 | 11157959 |
| overexpression of the response regulator evga of the two-component signal transduction system modulates multidrug resistance conferred by multidrug resistance transporters. | overexpression of evga, a response regulator of a two-component system, increased multidrug efflux in escherichia coli. since overexpression of the emrky operon, which is controlled by evgas, could account only for deoxycholate resistance, the evgas locus apparently controls expression of at least one other multidrug efflux operon. | 2001 | 11157960 |
| alpha(4) integrin-dependent eosinophil recruitment in allergic but not non-allergic inflammation. | 1. although anti-alpha(4) integrin mabs reduce eosinophil accumulation in several models of allergic inflammation, it is not clear whether this occurs via a direct action to block eosinophil alpha(4) integrins or indirectly on another cell type. the role of alpha(4) integrins on the accumulation of (111)in-labelled eosinophils in allergic and non-allergic inflammation in guinea-pig skin was therefore investigated. 2. intradermal injection of antigen in sensitized skin sites induced accumulation ... | 2001 | 11159710 |
| modulation of cytokine release in ex vivo-stimulated blood from borreliosis patients. | in lipopolysaccharide-stimulated blood from 71 late-stage borreliosis patients, the ex vivo cytokine release capacity of tumor necrosis factor alpha (tnf-alpha) and gamma interferon (ifn-gamma) was reduced to 28% +/- 5% and to 31% +/- 5% (p < or = 0.001), respectively, compared to that of 24 healthy controls. white blood cell counts were normal in both groups. to investigate direct interactions between the pathogen and the immune cells, blood from healthy controls was exposed in vitro to live or ... | 2001 | 11159956 |
| gene discovery through genomic sequencing of brucella abortus. | brucella abortus is the etiological agent of brucellosis, a disease that affects bovines and human. we generated dna random sequences from the genome of b. abortus strain 2308 in order to characterize molecular targets that might be useful for developing immunological or chemotherapeutic strategies against this pathogen. the partial sequencing of 1,899 clones allowed the identification of 1,199 genomic sequence surveys (gsss) with high homology (blast expect value < 10(-5)) to sequences deposite ... | 2001 | 11159979 |
| induction of neutralizing antibodies against diphtheria toxin by priming with recombinant mycobacterium bovis bcg expressing crm(197), a mutant diphtheria toxin. | bcg, the attenuated strain of mycobacterium bovis, has been widely used as a vaccine against tuberculosis and is thus an important candidate as a live carrier for multiple antigens. with the aim of developing a recombinant bcg (rbcg) vaccine against diphtheria, pertussis, and tetanus (dpt), we analyzed the potential of crm(197), a mutated nontoxic derivative of diphtheria toxin, as the recombinant antigen for a bcg-based vaccine against diphtheria. expression of crm(197) in rbcg was achieved usi ... | 2001 | 11159980 |
| initial characterization of the hemolysin stachylysin from stachybotrys chartarum. | stachybotrys chartarum is a toxigenic fungus that has been associated with human health concerns, including pulmonary hemorrhage and hemosiderosis. this fungus produces a hemolysin, stachylysin, which in its apparent monomeric form has a molecular mass of 11,920 da as determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry. however, it appears to form polydispersed aggregates, which confounds understanding of the actual hemolytically active form. exhaustive dia ... | 2001 | 11159985 |
| infectivity of chlamydia trachomatis serovar lgv but not e is dependent on host cell heparan sulfate. | the ability of heparan sulfate, heparin, and other glycosaminoglycans to inhibit the infectivity of chlamydia trachomatis serovars e and lgv was examined using a simple competitive inhibition assay with three cell types from the human female reproductive tract, including primary human endosalpingeal cells. with the majority of the glycosaminoglycans tested, lgv was more significantly inhibited than serovar e. we have compared chlamydial infectivity between a wild-type chinese hamster ovary cell ... | 2001 | 11159992 |
| the common vaccine adjuvant aluminum hydroxide up-regulates accessory properties of human monocytes via an interleukin-4-dependent mechanism. | aluminum adjuvants are widely used in human vaccines based on their ability to enhance antibody production. however, the mechanisms underlying these effects remain unknown. in the present study we assessed the direct in vitro effect of aluminum hydroxide on human peripheral blood monocytes, specifically with regard to its impact on the phenotype and functional properties of this cell population. our results revealed significant changes in the accessory properties of monocytes following short-ter ... | 2001 | 11160013 |
| expression of the moraxella catarrhalis uspa1 protein undergoes phase variation and is regulated at the transcriptional level. | the uspa1 protein of moraxella catarrhalis has been shown to function as an adhesin that mediates adherence to human epithelial cell lines in vitro (e. r. lafontaine, l. d. cope, c. aebi, j. l. latimer, g. h. mccracken, jr., and e. j. hansen, j. bacteriol. 182:1364-1373, 2000). in the present study, cell lysates prepared from individual colonies of several m. catarrhalis wild-type strains were analyzed by western blot analysis using monoclonal antibodies (mabs) specific for the uspa1 protein. ex ... | 2001 | 11160084 |
| nucleotide sequence and analysis of conjugative plasmid pvt745. | the complete nucleotide sequence and genetic map of pvt745 are presented. the 25-kb plasmid was isolated from actinobacillus actinomycetemcomitans, a periodontal pathogen. two-thirds of the plasmid encode functions related to conjugation, replication, and replicon stability. among potential gene products with a high degree of similarity to known proteins are those associated with plasmid conjugation. it was shown that pvt745 derivatives not only mobilized a coresident nontransmissible plasmid, p ... | 2001 | 11160089 |
| the binding subunit of pertussis toxin inhibits hiv replication in human macrophages and virus expression in chronically infected promonocytic u1 cells. | we have recently shown that the binding subunit of pertussis toxin (ptx-b) inhibits the entry and replication of macrophage-tropic (r5) hiv-1 strains in activated primary t lymphocytes. furthermore, ptx-b suppressed the replication of t cell-tropic (x4) viruses at a postentry level in the same cells. in this study we demonstrate that ptx-b profoundly impairs entry and replication of the hiv-1(ada) (r5), as well as of hiv pseudotyped with either murine leukemia virus or vesicular stomatitis virus ... | 2001 | 11160233 |
| inflammatory activation of neutrophils by helicobacter pylori; a mechanism insensitive to pertussis toxin. | chronic active gastritis of the antral mucosa is a characteristic feature of infection with helicobacter pylori and interactions between bacterial components and inflammatory cells are believed to play an important pathogenic role. neutrophils stimulated with h. pylori sonicate were demonstrated to release l-selectin (cd62l) expressed on the cellular surface, with a subsequent up-regulation of the beta2-integrins cd11b and cd11c, both in a dose- and time-dependent manner, reaching maximum levels ... | 2001 | 11168001 |
| identification of the nik gene cluster of brucella suis: regulation and contribution to urease activity. | analysis of a brucella suis 1330 gene fused to a gfp reporter, and identified as being induced in j774 murine macrophage-like cells, allowed the isolation of a gene homologous to nika, the first gene of the escherichia coli operon encoding the specific transport system for nickel. dna sequence analysis of the corresponding b. suis nik locus showed that it was highly similar to that of e. coli except for localization of the nikr regulatory gene, which lies upstream from the structural nikabcde ge ... | 2001 | 11133934 |
| fimw is a negative regulator affecting type 1 fimbrial expression in salmonella enterica serovar typhimurium. | type 1 fimbriae are proteinaceous surface appendages that carry adhesins specific for mannosylated glycoproteins. these fimbriae are found on most members of the family enterobacteriaceae and are known to facilitate binding to a variety of eukaryotic cells, including those found on the mucosal surfaces of the alimentary tract. we have shown that the regulation of type 1 fimbrial expression in salmonella enterica serovar typhimurium is controlled, in part, by the products of four genes found with ... | 2001 | 11133935 |
| transcriptional activation of bordetella alcaligin siderophore genes requires the alcr regulator with alcaligin as inducer. | genetic and biochemical studies have established that fur and iron mediate repression of bordetella alcaligin siderophore system (alc) genes under iron-replete nutritional growth conditions. in this study, transcriptional analyses using bordetella chromosomal alc-lacz operon fusions determined that maximal alc gene transcriptional activity under iron starvation stress conditions is dependent on the presence of alcaligin siderophore. mutational analysis and genetic complementation confirmed that ... | 2001 | 11133941 |
| genetic and biochemical analyses of bvga interaction with the secondary binding region of the fha promoter of bordetella pertussis. | the bvga-bvgs two-component signal transduction system regulates expression of virulence factors in bordetella pertussis. the bvga response regulator activates transcription by binding to target promoters, which include those for the genes encoding filamentous hemagglutinin (fha) and pertussis toxin (ptx). we have previously shown that at both promoters the phosphorylated form of bvga binds multiple high- and low-affinity sites. specifically, at the fha promoter, we proposed that there may be hi ... | 2001 | 11133947 |
| regulation of escherichia coli rela requires oligomerization of the c-terminal domain. | the e. coli rela protein is a ribosome-dependent (p)ppgpp synthetase that is activated in response to amino acid starvation. rela can be dissected both functionally and physically into two domains: the n-terminal domain (ntd) (amino acids [aa] 1 to 455) contains the catalytic domain of rela, and the c-terminal domain (ctd) (aa 455 to 744) is involved in regulating rela activity. we used mutational analysis to localize sites important for rela activity and control in these two domains. we inserte ... | 2001 | 11133950 |
| the absence of a flagellum leads to altered colony morphology, biofilm development and virulence in vibrio cholerae o139. | throughout most of history, epidemic and pandemic cholera was caused by vibrio cholerae of the serogroup o1. in 1992, however, a v. cholerae strain of the serogroup o139 emerged as a new agent of epidemic cholera. interestingly, v. cholerae o139 forms biofilms on abiotic surfaces more rapidly than v. cholerae o1 biotype el tor, perhaps because regulation of exopolysaccharide synthesis in v. cholerae o139 differs from that in o1 el tor. here, we show that all flagellar mutants of v. cholerae o139 ... | 2001 | 11136445 |
| limited genetic diversity of brucella spp. | multilocus enzyme electrophoresis (mlee) of 99 brucella isolates, including the type strains from all recognized species, revealed a very limited genetic diversity and supports the proposal of a monospecific genus. in mlee-derived dendrograms, brucella abortus and a marine brucella sp. grouped into a single electrophoretic type related to brucella neotomae and brucella ovis. brucella suis and brucella canis formed another cluster linked to brucella melitensis and related to rhizobium tropici. th ... | 2001 | 11136777 |
| ability of laboratories to detect emerging antimicrobial resistance: proficiency testing and quality control results from the world health organization's external quality assurance system for antimicrobial susceptibility testing. | the accuracy of antimicrobial susceptibility data submitted by microbiology laboratories to national and international surveillance systems has been debated for a number of years. to assess the accuracy of data submitted to the world health organization by users of the whonet software, the centers for disease control and prevention distributed six bacterial isolates representing key antimicrobial-resistance phenotypes to approximately 130 laboratories, all but one of which were outside of the un ... | 2001 | 11136778 |
| enterotoxigenic escherichia coli tiba glycoprotein adheres to human intestine epithelial cells. | enterotoxigenic escherichia coli (etec) is capable of invading epithelial cell lines derived from the human ileum and colon. two separate invasion loci (tia and tib) that direct noninvasive e. coli strains to adhere to and invade cultured human intestine epithelial cells have previously been isolated from the classical etec strain h10407. the tib locus directs the synthesis of tiba, a 104-kda outer membrane glycoprotein. synthesis of tiba is directly correlated with the adherence and invasion ph ... | 2001 | 11119488 |
| silencing and reactivation of urease in yersinia pestis is determined by one g residue at a specific position in the ured gene. | yersinia pestis, the plague agent, is a naturally nonureolytic microorganism, while all other yersinia species display a potent urease activity. in this report we demonstrate that y. pestis harbors a complete urease locus composed of three structural (ureabc) and four accessory (ureefgd) genes. absence of ureolytic activity is due to the presence of one additional g residue in a poly(g) stretch, which introduces a premature stop codon in ured. the presence of the same additional g in eight other ... | 2001 | 11119503 |
| susceptibility to secondary francisella tularensis live vaccine strain infection in b-cell-deficient mice is associated with neutrophilia but not with defects in specific t-cell-mediated immunity. | previous studies have demonstrated a role for b cells, not associated with antibody production, in protection against lethal secondary infection of mice with francisella tularensis live vaccine strain (lvs). however, the mechanism by which b cells contribute to this protection is not known. to study the specific role of b cells during secondary lvs infection, we developed an in vitro culture system that mimics many of the same characteristics of in vivo infection. using this culture system, we s ... | 2001 | 11119506 |
| invasion of human epithelial cells by pseudomonas aeruginosa involves src-like tyrosine kinases p60src and p59fyn. | pseudomonas aeruginosa plays a major role in respiratory tract infections or sepsis in patients with cystic fibrosis or upon suppression of the immune system. several p. aeruginosa strains have been shown to be internalized by human epithelial cells; however, the molecular mechanisms of the invasion process are poorly characterized. here, we show that the internalization of p. aeruginosa into human epithelial cells results in and requires activation of the src-like tyrosine kinases p59fyn and p6 ... | 2001 | 11119516 |
| mapping of binding domains of nontypeable haemophilus influenzae hmw1 and hmw2 adhesins. | nontypeable haemophilus influenzae is an important cause of localized respiratory tract disease, which begins with colonization of the upper respiratory mucosa. in previous work we reported that the nontypeable h. influenzae hmw1 and hmw2 proteins are high-molecular-weight nonpilus adhesins responsible for attachment to human epithelial cells, an essential step in the process of colonization. interestingly, although hmw1 and hmw2 share significant sequence similarity, they display distinct cellu ... | 2001 | 11119519 |
| temperature-regulated protein synthesis by leptospira interrogans. | leptospira interrogans is an important mammalian pathogen. transmission from an environmental source requires adaptations to a range of new environmental conditions in the organs and tissues of the infected host. since many pathogenic bacteria utilize temperature to discern their environment and regulate the synthesis of appropriate proteins, we investigated the effects of temperature on protein synthesis in l. interrogans. bacteria were grown for several days after culture temperatures were shi ... | 2001 | 11119530 |
| legionella pneumophila entry gene rtxa is involved in virulence. | successful parasitism of host cells by intracellular pathogens involves adherence, entry, survival, intracellular replication, and cell-to-cell spread. our laboratory has been examining the role of early events, adherence and entry, in the pathogenesis of the facultative intracellular pathogen legionella pneumophila. currently, the mechanisms used by l. pneumophila to gain access to the intracellular environment are not well understood. we have recently isolated three loci, designated enh1, enh2 ... | 2001 | 11119544 |
| control of the ferric citrate transport system of escherichia coli: mutations in region 2.1 of the feci extracytoplasmic-function sigma factor suppress mutations in the fecr transmembrane regulatory protein. | transcription of the ferric citrate transport genes is initiated by binding of ferric citrate to the feca protein in the outer membrane of escherichia coli k-12. bound ferric citrate does not have to be transported but initiates a signal that is transmitted by feca across the outer membrane and by fecr across the cytoplasmic membrane into the cytoplasm, where the feci extracytoplasmic-function (ecf) sigma factor becomes active. in this study, we isolated transcription initiation-negative missens ... | 2001 | 11114913 |
| initiation factor 2 of myxococcus xanthus, a large version of prokaryotic translation initiation factor 2. | we have isolated the structural gene for translation initiation factor if2 (infb) from the myxobacterium myxococcus xanthus. the gene (3.22 kb) encodes a 1,070-residue protein showing extensive homology within its g domain and c terminus to the equivalent regions of if2 from escherichia coli. the protein cross-reacts with antibodies raised against e. coli if2 and was able to complement an e. coli infb mutant. the m. xanthus protein is the largest if2 known to date. this is essentially due to a l ... | 2001 | 11114918 |
| characterization of in53, a class 1 plasmid- and composite transposon-located integron of escherichia coli which carries an unusual array of gene cassettes. | further characterization of the genetic environment of the gene encoding the escherichia coli extended-spectrum beta-lactamase, bla(veb-1), revealed the presence of a plasmid-located class 1 integron, in53, which carried eight functional resistance gene cassettes in addition to bla(veb-1). while the aadb and the arr-2 gene cassettes were identical to those previously described, the remaining cassettes were novel: (i) a novel nonenzymatic chloramphenicol resistance gene of the cmla family, (ii) a ... | 2001 | 11114922 |
| vibrio fischeri genes hvna and hvnb encode secreted nad(+)-glycohydrolases. | hvna and hvnb are proteins secreted by vibrio fischeri es114, an extracellular light organ symbiont of the squid euprymna scolopes, that catalyze the transfer of adp-ribose from nad(+) to polyarginine. based on this activity, hvna and hvnb were presumptively designated mono-adp-ribosyltransferases (artases), and it was hypothesized that they mediate bacterium-host signaling. we have cloned hvna and hvnb from strain es114. hvna appears to be expressed as part of a four-gene operon, whereas hvnb i ... | 2001 | 11114931 |
| genetic organization of the region encoding regulation, biosynthesis, and transport of rhizobactin 1021, a siderophore produced by sinorhizobium meliloti. | eight genes have been identified that function in the regulation, biosynthesis, and transport of rhizobactin 1021, a hydroxamate siderophore produced under iron stress by sinorhizobium meliloti. the genes were sequenced, and transposon insertion mutants were constructed for phenotypic analysis. six of the genes, named rhbabcdef, function in the biosynthesis of the siderophore and were shown to constitute an operon that is repressed under iron-replete conditions. another gene in the cluster, name ... | 2001 | 11274118 |
| rapid dephosphorylation of the torr response regulator by the tors unorthodox sensor in escherichia coli. | induction of the torcad operon, encoding the trimethylamine n-oxide (tmao) respiratory system, is tightly controlled by the tors-torr phosphorelay system in response to tmao availability. tors is an unorthodox sensor that contains three phosphorylation sites and transphosphorylates torr via a four-step phosphorelay, his443-->asp723-->his850-->asp(torr). in this study, we provide genetic evidence that tors can dephosphorylate phospho-torr when tmao is removed. dephosphorylation probably occurs by ... | 2001 | 11274133 |
| aging and calcitriol regulation of ip3 production in rat skeletal muscle and intestine. | we previously reported that calcitriol [1,25(oh)2-vitamin d3] in rat skeletal muscle and duodenum stimulates the hydrolysis of polyphosphoinositides by phospholipase c (plc), generating the second messengers inositol trisphosphate (ip3) and diacylglycerol (dag), and that this mechanism is altered in old animals. as previously reported in muscle, we show in the present study that gtpgammas (100 microm, 15 s), the non-hydrolyzable analogue of gtp, increased ip3 release from young rats duodenum to ... | 2001 | 11280708 |
| proline-rich peptide from the coral pathogen vibrio shiloi that inhibits photosynthesis of zooxanthellae. | the coral-bleaching bacterium vibrio shiloi biosynthesizes and secretes an extracellular peptide, referred to as toxin p, which inhibits photosynthesis of coral symbiotic algae (zooxanthellae). toxin p was produced during the stationary phase when the bacterium was grown on peptone or casamino acids media at 29 degrees c. glycerol inhibited the production of toxin p. toxin p was purified to homogeneity, yielding the following 12-residue peptide: pypvyapppvvp (molecular weight, 1,295.54). the str ... | 2001 | 11282602 |
| development of a genomics-based pcr assay for detection of mycoplasma pneumoniae in a large outbreak in new york state. | a genomics-based pcr method was developed and used to test specimens from patients involved in a large outbreak of mycoplasma pneumoniae in a closed religious community in new york state. new p1 adhesin gene primers were designed to bind to 9 of 10 target sequences in the repetitive-element sequences obtained from the whole genome sequence of m. pneumoniae. this pcr method had a sensitivity of 0.006 cfu and a specificity of 100% for m. pneumoniae. the pcr was validated by testing a subset of pat ... | 2001 | 11283060 |
| helicobacter pylori genetic diversity and risk of human disease. | 2001 | 11285290 | |
| pertussis toxin directly activates endothelial cell p42/p44 map kinases via a novel signaling pathway. | bordetella pertussis generates a bacterial toxin utilized in signal transduction investigation because of its ability to adp ribosylate specific g proteins. we previously noted that pertussis toxin (ptx) directly activates endothelial cells, resulting in disruption of monolayer integrity and intercellular gap formation via a signaling pathway that involves protein kinase c (pkc). we studied the effect of ptx on the activity of the 42- and 44-kda extracellular signal-regulated kinases (erk), memb ... | 2001 | 11287337 |
| schistosomiasis in the people's republic of china: prospects and challenges for the 21st century. | schistosomiasis japonica is a serious communicable disease and a major disease risk for more than 30 million people living in the tropical and subtropical zones of china. infection remains a major public health concern despite 45 years of intensive control efforts. it is estimated that 865,000 people and 100,250 bovines are today infected in the provinces where the disease is endemic, and its transmission continues. unlike the other schistosome species known to infect humans, the oriental schist ... | 2001 | 11292639 |
| bacterial infection in chronic obstructive pulmonary disease in 2000: a state-of-the-art review. | chronic obstructive pulmonary disease (copd) is the fourth leading cause of death in the united states. the precise role of bacterial infection in the course and pathogenesis of copd has been a source of controversy for decades. chronic bacterial colonization of the lower airways contributes to airway inflammation; more research is needed to test the hypothesis that this bacterial colonization accelerates the progressive decline in lung function seen in copd (the vicious circle hypothesis). the ... | 2001 | 11292642 |
| vaccination strategies for mucosal immune responses. | mucosal administration of vaccines is an important approach to the induction of appropriate immune responses to microbial and other environmental antigens in systemic sites and peripheral blood as well as in most external mucosal surfaces. the development of specific antibody- or t-cell-mediated immunologic responses and the induction of mucosally induced systemic immunologic hyporesponsiveness (oral or mucosal tolerance) depend on complex sets of immunologic events, including the nature of the ... | 2001 | 11292646 |
| search for correlates of protective immunity conferred by anthrax vaccine. | vaccination by anthrax protective antigen (pa)-based vaccines requires multiple immunization, underlying the need to develop more efficacious vaccines or alternative vaccination regimens. in spite of the vast use of pa-based vaccines, the definition of a marker for protective immunity is still lacking. here we describe studies designed to help define such markers. to this end we have immunized guinea pigs by different methods and monitored the immune response and the corresponding extent of prot ... | 2001 | 11292703 |
| role of helicobacter pylori cag region genes in colonization and gastritis in two animal models. | the helicobacter pylori chromosomal region known as the cytotoxin-gene associated pathogenicity island (cag pai) is associated with severe disease and encodes proteins that are believed to induce interleukin (il-8) secretion by cultured epithelial cells. the objective of this study was to evaluate the relationship between the cag pai, induction of il-8, and induction of neutrophilic gastric inflammation. germ-free neonatal piglets and conventional c57bl/6 mice were given wild-type or cag deficie ... | 2001 | 11292705 |
| brka protein of bordetella pertussis inhibits the classical pathway of complement after c1 deposition. | bordetella pertussis produces a 73-kda protein, brka (bordetella resistance to killing), which inhibits the bactericidal activity of complement. in this study we characterized the step in the complement cascade where brka acts, using three strains: a wild-type strain, a strain containing an insertional disruption of brka, and a strain containing two copies of the brka locus. following incubation with 10% human serum, killing was greatest for the brka mutant, followed by that for the wild-type st ... | 2001 | 11292725 |
| reversal of the cd4(+)/cd8(+) t-cell ratio in lymph node cells upon in vitro mitogenic stimulation by highly purified, water-soluble s3-s4 dimer of pertussis toxin. | pertussis toxin (pt), a holomer consisting of a catalytic s1 subunit and a b oligomer composed of s2-s4 and s3-s4 dimers, held together by the s5 subunit, exerts profound effects on immune cells, including t-cell mitogenicity. while the mitogenic activity of pt was shown to reside fully within the b oligomer, it could not be assigned to any particular b-oligomer component. in this study, we purified the s3-s4 dimer to homogeneity under conditions propitious to maintenance of the native conformat ... | 2001 | 11292726 |
| expression of the putative siderophore receptor gene bfrz is controlled by the extracytoplasmic-function sigma factor bupi in bordetella bronchiseptica. | a new gene from bordetella bronchiseptica, bfrz encoding a putative siderophore receptor, was identified in a fur-repressor titration assay. a bfrz null mutant was constructed by allelic exchange. the protein profile of this mutant is similar to that of the wild-type parent strain. the bfrz(-)-bfrz(+) isogenic pair was tested for utilization of 132 different siderophores as iron sources. none of these iron sources acted as a ligand for bfrz. translational bfrz::phoa and transcriptional bfrz::lac ... | 2001 | 11292812 |
| population-based incidence of pertussis among adolescents and adults, minnesota, 1995-1996. | to estimate the incidence of pertussis, a prospective study was done among members of a managed care organization in minneapolis/st. paul, minnesota. of 212 patients 10-49 years old enrolled from january 1995 through december 1996, 8 were found to be culture positive, 10 were found to be positive by polymerase chain reaction assay, 13 had a > or =2-fold increase in igg or iga to pertussis toxin (pt), and 18 had igg to pt in a single serum specimen > or =3 sd above the mean of an age-matched cont ... | 2001 | 11294666 |
| molecular epidemiology of bordetella pertussis by pulsed-field gel electrophoresis profile: cincinnati, 1989-1996. | reported cases of pertussis have increased in the united states, with peaks occurring every few years. bordetella pertussis isolates collected in cincinnati from 1989 to 1996 were analyzed with pulsed-field gel electrophoresis (pfge), to evaluate trends. among 496 isolates, 30 pfge profiles were identified; 32% were cyxxi-010, the profile that predominated each year. eighteen profiles (198 strains) were identified in 1989-1992, 20 profiles (197 strains) were identified during the 1993 epidemic, ... | 2001 | 11294667 |
| type iii secretion chaperone-dependent regulation: activation of virulence genes by sica and invf in salmonella typhimurium. | invasion of the intestinal epithelium by salmonella sp. requires a type iii secretion system (ttss) common in many bacterial pathogens. ttss translocate effector proteins from bacteria into eukaryotic cells. these effectors manipulate cellular functions in order to benefit the pathogen. in the human and animal pathogen salmonella typhimurium, the expression of genes encoding the secreted effector molecules sip/ssp abcd, sigd, sptp and sope requires both the arac/xyls-like regulator invf and the ... | 2001 | 11296219 |
| type iv secretion: intercellular transfer of macromolecules by systems ancestrally related to conjugation machines. | bacterial conjugation systems are highly promiscuous macromolecular transfer systems that impact human health significantly. in clinical settings, conjugation is exceptionally problematic, leading to the rapid dissemination of antibiotic resistance genes and other virulence traits among bacterial populations. recent work has shown that several pathogens of plants and mammals - agrobacterium tumefaciens, bordetella pertussis, helicobacter pylori and legionella pneumophila - have evolved secretion ... | 2001 | 11309113 |
| characterization of the type iii secretion locus of bordetella pertussis. | multiple sequence comparisons of proteins of the lcrd/flbf family allowed the design of primers that specifically amplify sequences coding for type iii secretion components. amplification of bordetella pertussis dna with these primers yielded a fragment that was further used as a probe for screening a genomic library. the nucleotide sequence of a positive clone revealed a 2100-bp gene, called bcrd, which specifies a 75-kda polypeptide homologous to the yersinia lcrd protein. chromosome walking a ... | 2001 | 11310448 |
| analysis of bordetella pertussis isolates collected in japan before and after introduction of acellular pertussis vaccines. | because of recent concern that whole-cell pertussis vaccination can drive antigenic divergence of circulating isolates of bordetella pertussis, we compared 12 clinical isolates of b. pertussis collected in japan, the first country to introduce acellular pertussis vaccines, with the vaccine strain. we used pulsed-field gel electrophoresis, sequencing of ptx and prn genes and expression of fimbriae. most of the isolates collected before or after introduction of acellular vaccine possess similar re ... | 2001 | 11312021 |
| neonatal pertussis requiring extracorporeal membrane oxygenation. | despite widespread immunization against bordetella pertussis, whooping cough remains potentially fatal in susceptible populations such as neonates. a case of neonatal pertussis with severe pulmonary hypertension (ph) requiring extracorporal membrane oxygenation (ecmo) is described. ph associated with pertussis severe enough to require ecmo is frequently irreversible and associated with a poor prognosis. | 2001 | 11315288 |
| recent progress in clinical and basic pertussis research. | over the last decade, substantial progress has been made in the field of pertussis research. this includes better understanding of virulence mechanisms and their influence on the pathogenicity of bordetella pertussis, increased awareness of the broad spectrum of disease and more insight into the host's immune response to infection, improved diagnostic tools, development, evaluation, introduction and implementation of several acellular pertussis vaccines and better understanding of the epidemiolo ... | 2001 | 11317640 |
| functional and mutational analysis of p19, a dna transfer protein with muramidase activity. | protein p19 encoded by the conjugative resistance plasmid r1 has been identified as being one member of a large family of muramidases encoded by bacteriophages and by type iii and type iv secretion systems. we carried out a mutational analysis to investigate the function of protein p19 and used in vivo complementation assays to test those of several p19 mutants. the results indicated that conserved residues present in the presumed catalytic center of p19 are absolutely essential for its function ... | 2001 | 11325947 |
| new tests for syphilis: rational design of a pcr method for detection of treponema pallidum in clinical specimens using unique regions of the dna polymerase i gene. | a sensitive and specific pcr method to detect treponema pallidum in clinical specimens was developed. pcr primers were designed based on two unique features of the dna polymerase i gene (pola). the first distinctive characteristic is that the region codes for a high cysteine content and has low homology with similar regions of dna polymerase i gene from known microorganisms. the second unique feature is the presence of four insertions in the gene. pcr tests using primers designed on the basis th ... | 2001 | 11326018 |
| real-time pcr assay targeting is481 of bordetella pertussis and molecular basis for detecting bordetella holmesii. | detection of bordetella holmesii by a real-time pcr assay targeting is481 of bordetella pertussis is reported. sequencing of is481-specific pcr products from b. pertussis and b. holmesii isolates revealed sequence homology. restriction fragment length polymorphism demonstrated a low copy number of is481-like sequences in b. holmesii. these results, and culture of b. holmesii from patients with cough, suggest that the specificity and predictive value of is481-based pcr assays for pertussis may be ... | 2001 | 11326023 |
| characterization of a monoclonal antibody that binds to an epitope on soluble bacterial peptidoglycan fragments. | we employed an inhibition-type enzyme-linked immunosorbent assay (elisa) to characterize a murine immunoglobulin m monoclonal antibody (mab) that bound soluble macromolecular peptidoglycan (pg). with this elisa, the mab was capable of detecting soluble pg concentrations of less than 10 ng/ml. enzymatic digestion of pg reduced binding by more than 100-fold, implying that the epitope recognized by this antibody depended on repeating subunits within the glycan backbone. additionally, the mab bound ... | 2001 | 11329475 |
| mass spectrometric analysis of recombinant adenylate cyclase toxin from bordetella pertussis strain 18323/phsp9. | the adenylate cyclase toxin-hemolysin (act) is a key virulence factor of the whooping cough agent bordetella pertussis (bp). the major cytotoxic activity of this 1706-residue protein consists of its capacity to invade a variety of eukaryotic cells directly across their cytoplasmic membrane and to deliver into cells a catalytic adenylate cyclase domain. this causes impairment of immune effector cells and apoptosis of lung macrophages by uncontrolled conversion of atp to camp. the adenylate cyclas ... | 2001 | 11333441 |
| evaluation of a real-time pcr assay for detection of bordetella pertussis and b. parapertussis in clinical samples. | a real-time pcr assay based on the taqman technology was developed for the detection of bordetella pertussis and b. parapertussis in clinical samples. the assay was evaluated with 182 specimens from 153 patients with and without symptoms of pertussis. the analytical sensitivity ranged from 0.1 to 10 cfu for b. pertussis and b. parapertussis, respectively, and diagnostic sensitivity was 94.1% when culture was used as a reference. no sample from a patient without symptoms of pertussis was positive ... | 2001 | 11339251 |
| the adenylate cyclase toxin of bordetella pertussis binds to target cells via the alpha(m)beta(2) integrin (cd11b/cd18). | the adenylate cyclase toxin (cyaa) of bordetella pertussis is a major virulence factor required for the early phases of lung colonization. it can invade eukaryotic cells where, upon activation by endogenous calmodulin, it catalyzes the formation of unregulated camp levels. cyaa intoxication leads to evident toxic effects on macrophages and neutrophils. here, we demonstrate that cyaa uses the alpha(m)beta(2) integrin (cd11b/cd18) as a cell receptor. indeed, the saturable binding of cyaa to the su ... | 2001 | 11342588 |
| adenylate kinase as a virulence factor of pseudomonas aeruginosa. | adenylate kinase (ak; atp:amp phosphotransferase, ec 2.7.4.3) is a ubiquitous enzyme that contributes to the homeostasis of adenine nucleotides in eukaryotic and prokaryotic cells. ak catalyzes the reversible reaction mg. atp + amp <--> mg. adp + adp. in this study we show that ak secreted by the pathogenic strains of pseudomonas aeruginosa appears to play an important role in macrophage cell death. we purified and characterized ak from the growth medium of a cystic fibrosis isolate strain of p. ... | 2001 | 11344142 |
| the virulence factors of bordetella pertussis: a matter of control. | bordetella pertussis is the causative agent of whooping cough, a contagious childhood respiratory disease. increasing public concern over the safety of whole-cell vaccines led to decreased immunisation rates and a subsequent increase in the incidence of the disease. research into the development of safer, more efficacious, less reactogenic vaccine preparations was concentrated on the production and purification of detoxified b. pertussis virulence factors. these virulence factors include adhesin ... | 2001 | 11348687 |
| formulation and characterisation of bordetella pertussis fimbriae as novel carrier proteins for hib conjugate vaccines. | haemophilus influenzae type b (hib) capsular polysaccharide (polyribosylribitol phosphate, prp) is the active component of conjugate vaccines that have proven successful in preventing invasive hib disease. conjugation of prp to a protein carrier greatly improves its immunogenicity providing protection in infants and subsequent antibody maturation upon boosting. in this study, fimbriae isolated from bordetella pertussis have been assessed as novel carrier proteins. these proteins are components o ... | 2001 | 11348704 |
| differential interleukin-10 and gamma interferon mrna expression in lungs of cilium-associated respiratory bacillus-infected mice. | the cilium-associated respiratory (car) bacillus is a gram-negative, extracellular bacterium that causes persistent respiratory tract infections in rodents. we have previously demonstrated that balb/c mice are more susceptible to car bacillus-induced disease than resistant c57bl/6 mice, with elevations in pulmonary gamma interferon (ifn-gamma) and interleukin (il)-4. il-10 is a type 2 cytokine that can increase host susceptibility to bacterial diseases through its anti-inflammatory effects, incl ... | 2001 | 11349033 |
| influence of vector-encoded cytokines on anti-salmonella immunity: divergent effects of interleukin-2 and tumor necrosis factor alpha. | attenuated salmonella strains are of interest as new vaccine candidates and as vectors of cloned genes of other organisms. attenuated strains expressing specific cytokines were constructed as a means of manipulating the immune response in various disease settings. in the present study, interleukin-2 (il-2)-expressing (gidil2) or tumor necrosis factor alpha (tnf-alpha)-expressing (gidtnf) strains were compared with the parent strain (brd509) for the effect of cytokines on anti-salmonella immunity ... | 2001 | 11349067 |
| intracellular survival of brucella spp. in human monocytes involves conventional uptake but special phagosomes. | brucella spp. are facultative intracellular parasites of various mammals, including humans, typically infecting lymphoid as well as reproductive organs. we have investigated how b. suis and b. melitensis enter human monocytes and in which compartment they survive. peripheral blood monocytes readily internalized nonopsonized brucellae and killed most of them within 12 to 18 h. the presence of brucella-specific antibodies (but not complement) increased the uptake of bacteria without increasing the ... | 2001 | 11349069 |
| vaccination with bordetella pertussis-pulsed autologous or heterologous dendritic cells induces a mucosal antibody response in vivo and protects against infection. | this study demonstrates for the first time that vaccination with either autologous or heterologous dendritic cells (dc) pulsed with specific antigen induces protective immune responses against noninvasive bacteria, namely bordetella pertussis. the dc-mediated protection is associated with strong b. pertussis-specific immunoglobulin g (igg) and iga responses in the lung. | 2001 | 11349085 |
| differential prevention of morphine amnesia by antisense oligodeoxynucleotides directed against various gi-protein alpha subunits. | the effect of the i.c.v. administration of pertussis toxin (ptx) and antisense oligodeoxynucleotide directed against the alpha subunit of different gi-proteins (anti-gialpha1, anti-gialpha2, anti-gialpha3) on amnesia induced by morphine was evaluated in the mouse passive avoidance test. the administration of morphine (6 - 10 mg kg(-1) i.p.) immediately after the training session produced amnesia that was prevented by ptx (0.25 microg per mouse i.c.v.) administered 7 days before the passive avoid ... | 2001 | 11350863 |
| bordetella pertussis detection by spectrofluorometry using polymerase chain reaction (pcr) and a molecular beacon probe. | bordetella pertussis was detected by spectrofluorometry following pcr incorporating a molecular beacon probe in the reaction. a dna fragment from the tandem repeat sequence region (is 481) of the genome of b. pertussis was amplified in presence of the probe complementary to an internal segment of the amplified dna fragment. fluorescein (fam) and dabcyl were used as the fluorophore and quencher in the probe. the probe was characterized for its signal to noise ratio by homogeneous solution hybridi ... | 2001 | 11352597 |
| fimbrial typing of bordetello pertussis isolates: agglutination with polyclonal and monoclonal antisera. | 2001 | 11354036 | |
| diversity in the bordetella virulence regulon: transcriptional control of a bvg-intermediate phase gene. | the bvgas signal transduction system controls the expression of at least three distinct phenotypic phases that lie along a continuum of gene expression states. the bvg+ phase is characterized by the expression of adhesins and toxins, whereas the bvg- phase is characterized by motility in bordetella bronchiseptica and the expression of vrg loci in bordetella pertussis. the bvg-intermediate (bvgi) phase is characterized by the absence of bvg-repressed phenotypes, the expression of some, but not al ... | 2001 | 11359572 |
| pertussis is a frequent cause of prolonged cough illness in adults and adolescents. | although pertussis is increasingly recognized as a cause of prolonged cough illness in adolescents and adults, its prevalence is not well established. we evaluated pertussis infection in 442 adolescents and adults > or = 12 years old (mean age, 41.3 years) who had a cough-related illness of 7--56 days' duration. for 4 patients (0.9%), results of nasopharyngeal culture or pcr were positive for bordetella pertussis; for 10 patients (2.3%), either results of culture or pcr were positive or pertussi ... | 2001 | 11360208 |
| the luxm homologue vanm from vibrio anguillarum directs the synthesis of n-(3-hydroxyhexanoyl)homoserine lactone and n-hexanoylhomoserine lactone. | vibrio anguillarum, which causes terminal hemorrhagic septicemia in fish, was previously shown to possess a luxri-type quorum-sensing system (vanri) and to produce n-(3-oxodecanoyl)homoserine lactone (3-oxo-c10-hsl). however, a vani null mutant still activated n-acylhomoserine lactone (ahl) biosensors, indicating the presence of an additional quorum-sensing circuit in v. anguillarum. in this study, we have characterized this second system. using high-pressure liquid chromatography in conjunction ... | 2001 | 11371516 |
| genetic characterization of the klebsiella pneumoniae waa gene cluster, involved in core lipopolysaccharide biosynthesis. | a recombinant cosmid containing genes involved in klebsiella pneumoniae c3 core lipopolysaccharide biosynthesis was identified by its ability to confer bacteriocin 28b resistance to escherichia coli k-12. the recombinant cosmid contains 12 genes, the whole waa gene cluster, flanked by kbl and coad genes, as was found in e. coli k-12. pcr amplification analysis showed that this cluster is conserved in representative k. pneumoniae strains. partial nucleotide sequence determination showed that the ... | 2001 | 11371519 |
| ralstonia solanacearum needs motility for invasive virulence on tomato. | ralstonia solanacearum, a widely distributed and economically important plant pathogen, invades the roots of diverse plant hosts from the soil and aggressively colonizes the xylem vessels, causing a lethal wilting known as bacterial wilt disease. by examining bacteria from the xylem vessels of infected plants, we found that r. solanacearum is essentially nonmotile in planta, although it can be highly motile in culture. to determine the role of pathogen motility in this disease, we cloned, charac ... | 2001 | 11371523 |
| functional analysis of the agrobacterium tumefaciens t-dna transport pore protein virb8. | the virb8 protein of agrobacterium tumefaciens is essential for dna transfer to plants. virb8, a 237-residue polypeptide, is an integral membrane protein with a short n-terminal cytoplasmic domain. it interacts with two transport pore proteins, virb9 and virb10, in addition to itself. to study the role of these interactions in dna transfer and to identify essential amino acids of virb8, we introduced random mutations in virb8 by the mutagenic pcr method. the putative mutants were tested for virb ... | 2001 | 11371528 |
| virb7 lipoprotein is exocellular and associates with the agrobacterium tumefaciens t pilus. | agrobacterium tumefaciens transfers oncogenic t-dna and effector proteins to plant cells via a type iv secretion pathway. this transfer system, assembled from the products of the virb operon, is thought to consist of a transenvelope mating channel and the t pilus. when screened for the presence of virb and vire proteins, material sheared from the cell surface of octopine strain a348 was seen to possess detectable levels of virb2 pilin, virb5, and the virb7 outer membrane lipoprotein. material sh ... | 2001 | 11371529 |
| reconstitution of acetosyringone-mediated agrobacterium tumefaciens virulence gene expression in the heterologous host escherichia coli. | the ability to utilize escherichia coli as a heterologous system in which to study the regulation of agrobacterium tumefaciens virulence genes and the mechanism of transfer dna (t-dna) transfer would provide an important tool to our understanding and manipulation of these processes. we have previously reported that the rpoa gene encoding the alpha subunit of rna polymerase is required for the expression of lacz gene under the control of virb promoter (virbp::lacz) in e. coli containing a constit ... | 2001 | 11371534 |
| invasion of human respiratory epithelial cells by bordetella pertussis: possible role for a filamentous hemagglutinin arg-gly-asp sequence and alpha5beta1 integrin. | bordetella pertussis, the agent of whooping cough, is capable of invading human respiratory epithelial cells. in this study, we investigated the mechanisms by which b. pertussis invades the human lung epithelial cell line a549 and normal human bronchial epithelial (nhbe) cells. in vitro adhesion and invasion assays using both cell types with a virulent b. pertussis strain and its isogenic mutants revealed profound defects in a mutant deficient in filamentous hemagglutinin (fha) expression. in ad ... | 2001 | 11373122 |
| [post-vaccination granuloma due to aluminium hydroxide]. | post-vaccination granulomas a well-known reaction due to aluminium adsorbed vaccines. we report three cases of children who developed subcutaneous nodules at the site of a previous injection of tetracoq*vaccine (tetanus, diphtheria, bordetella pertussis, poliovirus). histologically, the lesions were characterized by a necrotizing granulomatous reaction with eosinophilic crystalline material. this material stained positively with the solochrome cyanine stain and was pink-purple. this aluminium st ... | 2001 | 11373585 |
| targeting to fcgamma receptors, but not cr3 (cd11b/cd18), increases clearance of bordetella pertussis. | in the absence of opsonizing antibodies, bordetella pertussis, the causative agent of pertussis, readily binds to phagocytes via complement receptor 3 (cr3). after opsonization with antibodies, binding is mediated by igg receptors (fcgammar). the effect of targeting b. pertussis to either fcgammar or cr3 was studied. the fate of unopsonized b. pertussis, igg-opsonized b. pertussis, and b. pertussis opsonized with bispecific antibodies (bsabs) directed to cr3 or fcgammarii/-iii was compared. igg ... | 2001 | 11237803 |