Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| effect of nimodipine on infectious brain edema in rabbits. | to study the effect of nimodipine (nim) on infectious brain edema (be). | 1996 | 9812737 |
| the filamentous hemagglutinin of bordetella parapertussis is the major adhesin in the phase-dependent interaction with nci-h292 human lung epithelial cells. | bordetella parapertussis is a gram-negative bacterium which colonizes the human respiratory tract and can cause whooping cough or pertussis. this pathogen is subject to phase variation and expresses a series of virulence factors exclusively in the bvg+ phase. here, it is demonstrated for the first time that only the bvg+ phase of b. parapertussis adheres to and invades the human lung epithelial cell line nci-h292. a b. parapertussis mutant defective in expression of the bvg+-regulated filamentou ... | 1998 | 9813157 |
| a sustained increase in the endogenous level of camp reduces the retinoid concentration required for apl cell maturation to near physiological levels. | camp-dependent signal transduction co-operates with retinoids to induce acute promyelocytic leukaemia (apl) cell maturation. the rationale of this work was to determine whether signal cross-talk could be used to decrease the pharmacological doses of retinoids in the treatment of apl. when only the basal level of adenylate-cyclase (ac) activity is present in nb4 cells, up to 1 microm concentration of all-trans retinoic acid (ra) is required for full maturation (100%). in these conditions, with on ... | 1998 | 9823961 |
| the lipopolysaccharide of bordetella bronchiseptica acts as a protective shield against antimicrobial peptides. | resistance profiles of the two bordetella species b. bronchiseptica and b. pertussis against various antimicrobial peptides were determined in liquid survival and agar diffusion assays. b. bronchiseptica exhibited significantly higher resistance against all tested peptides than b. pertussis. the most powerful agents acting on b. bronchiseptica were, in the order of their killing efficiencies, cecropin p > cecropin b > magainin-ii-amide > protamine > melittin. interestingly, for b. bronchiseptica ... | 1998 | 9826332 |
| activity of the mitogenic pasteurella multocida toxin requires an essential c-terminal residue. | pasteurella multocida toxin (pmt) is a potent mitogen that also affects bone resorption. pmt acts intracellularly and is therefore postulated to have several domains involved in different aspects of its function. the toxin contains eight cysteine residues. mutants with individual substitutions for each of these residues were constructed, and the effects of these on the biological activity of the toxin were determined by cultured-cell assays. only the most c-terminal of the eight cysteines (c1165 ... | 1998 | 9826336 |
| systemic and mucosal immune responses after intranasal administration of recombinant mycobacterium bovis bacillus calmette-guérin expressing glutathione s-transferase from schistosoma haematobium. | a major goal of current vaccine development is the induction of strong immune responses against protective antigens delivered by mucosal routes. one of the most promising approaches in that respect relies on the use of live recombinant vaccine carriers. in this study, mycobacterium bovis bcg was engineered to produce an intracellular glutathione s-transferase from schistosoma haematobium (sh28gst). the gene encoding sh28gst was placed under the control of the mycobacterial hsp60 promoter on a re ... | 1998 | 9826340 |
| intranasal immunization with cytotoxic t-lymphocyte epitope peptide and mucosal adjuvant cholera toxin: selective augmentation of peptide-presenting dendritic cells in nasal mucosa-associated lymphoid tissue. | we previously reported that cholera toxin (ct) was required as a mucosal adjuvant for the induction of peptide-specific cytotoxic t lymphocytes (ctl) following intranasal immunization with ctl epitope peptides (a. porgador et al., j. immunol. 158:834-841, 1997). the present study was performed to identify the site and the antigen-presenting cell (apc) population responsible for the presentation of intranasally administered ctl epitope peptide immunogens and to determine whether ct directly affec ... | 1998 | 9826368 |
| filamentous hemagglutinin of bordetella bronchiseptica is required for efficient establishment of tracheal colonization. | adherence to ciliated respiratory epithelial cells is considered a critical early step in bordetella pathogenesis. for bordetella pertussis, the etiologic agent of whooping cough, several factors have been shown to mediate adherence to cells and cell lines in vitro. these putative adhesins include filamentous hemagglutinin (fha), fimbriae, pertactin, and pertussis toxin. determining the precise roles of each of these factors in vivo, however, has been difficult, due in part to the lack of natura ... | 1998 | 9826374 |
| phosphatidylcholine-specific phospholipase c from listeria monocytogenes is an important virulence factor in murine cerebral listeriosis. | meningoencephalitis is a serious and often fatal complication of listeria monocytogenes infection. the aim of the present study was to analyze the role of internalin a (inla) and b, which are involved in the invasion of l. monocytogenes into cultivated host tissue cells, and that of phosphatidylcholine-specific phospholipase c (plcb), which mainly promotes the direct cell-to-cell spread of l. monocytogenes, in murine cerebral listeriosis by use of an inla/b (deltainlab2)- and a plcb (deltaplcb2) ... | 1998 | 9826375 |
| characterization of proteus mirabilis precocious swarming mutants: identification of rsba, encoding a regulator of swarming behavior. | proteus mirabilis swarming behavior is characterized by the development of concentric rings of growth that are formed as cyclic events of swarmer cell differentiation, swarming migration, and cellular differentiation are repeated during colony translocation across a surface. this cycle produces the bull's-eye colony often associated with cultures of p. mirabilis. how the cells communicate with one another to coordinate these perfectly synchronized rings is presently unknown. we report here the i ... | 1998 | 9829920 |
| genetic and sequence analysis of the ptic58 trb locus, encoding a mating-pair formation system related to members of the type iv secretion family. | conjugal transfer of ptic58 requires two regions, tra which contains the orit and several genes involved in dna processing and a region of undefined size and function that is located at the 2-o'clock position of the plasmid. using transposon mutagenesis with tn3hoho1 and a binary transfer system, we delimited this second region, called trb, to an 11-kb interval between the loci for vegetative replication and nopaline catabolism. dna sequence analysis of this region identified 13 significant open ... | 1998 | 9829924 |
| characterization of corr, a transcriptional activator which is required for biosynthesis of the phytotoxin coronatine. | coronatine (cor) is a plasmid-encoded phytotoxin synthesized by several pathovars of phytopathogenic pseudomonas syringae. the cor biosynthetic gene cluster in p. syringae pv. glycinea pg4180 is encoded by a 32-kb region which contains both the structural and regulatory genes needed for cor synthesis. the regulatory region contains three genes: corp, cors, and corr. cors is thought to function as a histidine protein kinase, whereas corp and corr show relatedness to response regulators of the two ... | 1998 | 9829934 |
| microbial genome sequencing-beyond the double helix. | 1998 | 9836662 | |
| ecls in pertussis: does it have a role? | to investigate the value of extracorporeal circulatory life support (ecls) in paediatric patients with severe bordetella pertussis infection. | 1998 | 9840245 |
| the virulence plasmid of yersinia, an antihost genome. | the 70-kb virulence plasmid enables yersinia spp. (yersinia pestis, y. pseudotuberculosis, and y. enterocolitica) to survive and multiply in the lymphoid tissues of their host. it encodes the yop virulon, an integrated system allowing extracellular bacteria to disarm the cells involved in the immune response, to disrupt their communications, or even to induce their apoptosis by the injection of bacterial effector proteins. this system consists of the yop proteins and their dedicated type iii sec ... | 1998 | 9841674 |
| neonatal exposure to a self-peptide-immunoglobulin chimera circumvents the use of adjuvant and confers resistance to autoimmune disease by a novel mechanism involving interleukin 4 lymph node deviation and interferon gamma-mediated splenic anergy. | induction of neonatal t cell tolerance to soluble antigens requires the use of incomplete freund's adjuvant (ifa). the side effects that could be associated with ifa and the ill-defined mechanism underlying neonatal tolerance are setbacks for this otherwise attractive strategy for prevention of t cell-mediated autoimmune diseases. presumably, ifa contributes a slow antigen release and induction of cytokines influential in t cell differentiation. immunoglobulins (igs) have long half-lives and cou ... | 1998 | 9841915 |
| suppressive effects of antihistaminic and/or anti-paf agents on passive anaphylactic shock in mice sensitized with allogeneic monoclonal ige and igg1 antibodies and hyperimmune serum. | for the immunopharmacological characterization of murine passive anaphylactic shock, the effects of antihistaminics and/or anti-platelet-activating factor (anti-paf) agents were studied on the shock mediated by allogeneic monoclonal ige and igg1 antibodies and hyperimmune serum. ige antibody-mediated shock was strongly suppressed by cyproheptadine (10 mg/kg, ip) in every strain regardless of the age and sex of the mice and the presence or absence of a shock potentiator. as far as tested with cts ... | 1998 | 9845423 |
| asymptomatic simian immunodeficiency virus infection decreases blood cd4(+) t cells by accumulating recirculating lymphocytes in the lymphoid tissues. | declining blood cd4(+) t-cell counts mark the progress of simian immunodeficiency virus (siv) disease in macaques and model the consequences of untreated human immunodeficiency virus infection in humans. however, blood lymphocytes are only a fraction of the recirculating lymphocyte pool, and their numbers are affected by cell synthesis, cell depletion, and distribution among blood and lymphoid tissue compartments. asymptomatic, siv-infected macaques maintained constant and nearly normal numbers ... | 1999 | 9847365 |
| incp plasmids are unusually effective in mediating conjugation of escherichia coli and saccharomyces cerevisiae: involvement of the tra2 mating system. | mobilizable shuttle plasmids containing the origin-of-transfer (orit) region of plasmids f (incfi), colib-p9 (inci1), and rp4/rp1 (incpalpha) were constructed to test the ability of the cognate conjugation system to mediate gene transfer from escherichia coli to saccharomyces cerevisiae. only the palpha system caused detectable mobilization to yeast, giving peak values of 5 x 10(-5) transconjugants per recipient cell in 30 min. transfer of the shuttle plasmid required carriage of orit in cis and ... | 1998 | 9851996 |
| stability of the agrobacterium tumefaciens virb10 protein is modulated by growth temperature and periplasmic osmoadaption. | export of oncogenic t-dna from the phytopathogen agrobacterium tumefaciens is mediated by the products of the virb operon. it has recently been reported (k. j. fullner and e. w. nester, j. bacteriol. 178:1498-1504, 1996) that dna transfer does not occur at elevated temperatures; these observations correlate well with much earlier studies on the temperature sensitivity of crown gall tumor development on plants. in testing the hypothesis that this loss of dna movement reflects a defect in assembly ... | 1998 | 9852004 |
| the two-component regulators gacs and gaca influence accumulation of the stationary-phase sigma factor sigmas and the stress response in pseudomonas fluorescens pf-5. | three global regulators are known to control antibiotic production by pseudomonas fluorescens. a two-component regulatory system comprised of the sensor kinase gacs (previously called apda or lema) and gaca, a member of the fixj family of response regulators, is required for antibiotic production. a mutation in rpos, which encodes the stationary-phase sigma factor sigmas, differentially affects antibiotic production and reduces the capacity of stationary-phase cells of p. fluorescens to survive ... | 1998 | 9852008 |
| selectivity of ferric enterobactin binding and cooperativity of transport in gram-negative bacteria. | the ligand-gated outer membrane porin fepa serves escherichia coli as the receptor for the siderophore ferric enterobactin. we characterized the ability of seven analogs of enterobactin to supply iron via fepa by quantitatively measuring the binding and transport of their 59fe complexes. the experiments refuted the idea that chirality of the iron complex affects its recognition by fepa and demonstrated the necessity of an unsubstituted catecholate coordination center for binding to the outer mem ... | 1998 | 9852016 |
| comparison of pcr, culture, and serological tests for diagnosis of mycoplasma pneumoniae respiratory tract infection in children. | for diagnosis of mycoplasma pneumoniae infection we compared two rapid tests, pcr and the immunoglobulin m immunofluorescence assay (igm ifa), with culture and the complement fixation test (cft), in a prospective study among 92 children with respiratory tract infection and 74 controls. based on positivity of culture and/or cft as the diagnostic criterion, nine patients (10%) were diagnosed with m. pneumoniae infection. all patients positive by culture were also positive by pcr. in all controls c ... | 1999 | 9854056 |
| a respiratory challenge model for infection with bordetella pertussis: application in the assessment of pertussis vaccine potency and in defining the mechanism of protective immunity. | the evaluation of vaccines for human use usually requires the development of appropriate animal models and the definition of laboratory correlates of immunity. traditionally whole cell pertussis vaccines have been controlled by using an active mouse protection test, which measures protection following intracerebral challenge with bordetella pertussis. however, this test is unsuitable for assessing the potency of the new generation acellular pertussis vaccines. in the present study we demonstrate ... | 1998 | 9855412 |
| [evaluation of the usefulness of bordetella pertussis toxins for serodiagnosis of whooping cough]. | the results of serological tests for the detection of antibodies against pertussis toxin by means of the elisa test, and endotoxin of b. pertussis in the passive haemagglutination test were analysed. the levels of igg, igm and iga antibodies were determined for 95% of serum samples of 108 children in control group (without evidence of respiratory infections) for establishing of the correlation of these with the age of these children. in the light of these data the results were evaluated of testi ... | 1998 | 9857618 |
| nucleotide sequences of genes coding for fimbrial proteins in a cryptic genospecies of haemophilus spp. isolated from neonatal and genital tract infections. | nineteen isolates belonging to a cryptic genospecies of haemophilus (referred to here as genital strains) isolated from genital tract infections (6 strains) and from neonatal infections (13 strains) were studied for fimbrial genes. sixteen strains exhibit peritrichous fimbriae observed by electron microscopy. by pcr with primers corresponding to the extreme ends of the haemophilus influenzae type b (hib) hifa and hifd genes and southern blotting, a hifa-like gene (named ghfa) and a hifd-like gen ... | 1999 | 9864189 |
| immunogenicity of intranasally administered meningococcal native outer membrane vesicles in mice. | colonization of the human nasopharyngeal region by neisseria meningitidis is believed to lead to natural immunity. although the presence of bactericidal antibody in serum has been correlated with immunity to meningococcal disease, mucosal immunity at the portal of entry may also play an important role. this study was undertaken to examine in mice the possibility of safely using native outer membrane vesicles (nomv) not exposed to detergent as an intranasal (i.n.) vaccine. the mucosal and systemi ... | 1999 | 9864204 |
| nonrestricted differential intoxication of cells by pertussis toxin. | after uptake and retrograde transport pertussis toxin acts by adp-ribosylating alpha-gi proteins. we show that uptake via many different receptor proteins followed by retrograde transport and intoxication is not restricted to a particular cell type. the efficiency of cellular intoxication, however, was found to be cell type dependent. | 1999 | 9864250 |
| adhesin expression in matched nasopharyngeal and middle ear isolates of nontypeable haemophilus influenzae from children with acute otitis media. | the hmw1 and hmw2 proteins, hia, and hemagglutinating pili are important adherence factors in nontypeable haemophilus influenzae. to gain insight into the relative importance of these adhesins in nasopharyngeal colonization and localized respiratory tract disease, we assessed their expression in matched nasopharyngeal and middle ear isolates of nontypeable h. influenzae from 17 children with acute otitis media. in all patients, including 11 with bilateral disease, the matched isolates were isoge ... | 1999 | 9864255 |
| etiology of respiratory tract infection in adults in a general practice setting. | a prospective study was conducted over a 3-month winter period in three general practice clinics in an urban population in southern israel to identify the etiological agents of respiratory tract infections (rti) in adults. rti was defined as an acute febrile illness with cough, coryza, sore throat or hoarseness. serum samples were taken from all patients in both the acute and convalescent phases of their illness. tests were conducted for detection of 17 microorganisms known to cause rti, includi ... | 1998 | 9865980 |
| [changes of nmda receptor gene expression in infection brain injury induced by bordetella pertussis in rats]. | n-methyl-d-aspartate receptors (nmdar) in cerebral cortexes of rat brain injury induced by bordetella pertussis (bp) were measured by methods of northern blot analysis and [3h] mk-801 radioligand-receptor binding to study changes and effects of nmdar1 of gene expression in the infection brain injury. the affinity (kd) of nmdar in bp group was significantly decreased [30.5 +/- 3.0 nmol.l-1 (bp), 43.1 +/- 4.2 nmol.l-1 (ns), p < 0.05], but expression of nmdar1 mrna and binding site density (bmax) o ... | 1997 | 9868018 |
| [delayed brain injury induced by bordetella pertussis in rats]. | to induced new model of delayed infection brain injury, we divided randomly 40 adult male sprague-dawley rats into four groups: bordetella pertussis (bp) groups, and normal sailine (ns) groups in 4 h (n = 10) and 24 h (n = 10), respectively, injected bp at 0.2 ml.kg-1 which contained the bacilli in 10.8 x 10(9).ml-1 into the rat left internal carotid artery of bp groups, and injected at the equal volume as control in the same way into ns groups. the water content (wc), evans blue content (eb), c ... | 1997 | 9868080 |
| adp-ribosylation as an intermediate step in inactivation of rifampin by a mycobacterial gene. | mycobacterium smegmatis dsm43756 inactivates rifampin, and the inactivated antibiotic product recovered from culture medium was ribosylated on the 23-oh group. to study this process, the gene responsible for the inactivation was expressed at high levels by the lac promoter in escherichia coli conferring resistance to >500 microg of antibiotic per ml. cell homogenates generated a novel derivative designated rip-tas; in this study, we determined that rip-tas is 23-(o-adp-ribosyl)rifampin. our resu ... | 1999 | 9869590 |
| detection of bordetella pertussis and respiratory synctial virus in air samples from hospital rooms. | to evaluate the distribution of bordetella pertussis and respiratory syncytial virus (rsv) in the hospital setting. | 1998 | 9872529 |
| a natural variant of the cysteine protease virulence factor of group a streptococcus with an arginine-glycine-aspartic acid (rgd) motif preferentially binds human integrins alphavbeta3 and alphaiibbeta3. | the human pathogenic bacterium group a streptococcus produces an extracellular cysteine protease [streptococcal pyrogenic exotoxin b (speb)] that is a critical virulence factor for invasive disease episodes. sequence analysis of the speb gene from 200 group a streptococcus isolates collected worldwide identified three main mature speb (mspeb) variants. one of these variants (mspeb2) contains an arg-gly-asp (rgd) sequence, a tripeptide motif that is commonly recognized by integrin receptors. mspe ... | 1999 | 9874803 |
| expression of heat-shock proteins in streptococcus pyogenes and their immunoreactivity with sera from patients with streptococcal diseases. | the heat-shock response of streptococcus pyogenes following exposure to elevated growth temperatures, and the immunological reactivity of heat-shock proteins (hsps) in streptococcal infections were studied. two major proteins of 65 and 75 kda were expressed when a s. pyogenes strain was shifted from 37 degrees c to heat-shock temperatures of 40, 42 and 45 degrees c. such proteins are members of the groel and dnak families recognised in a western blot assay with polyclonal antibodies against esch ... | 1998 | 9877192 |
| role of heat shock proteins in protection from and pathogenesis of infectious diseases. | increased synthesis of heat shock proteins (hsp) occurs in prokaryotic and eukaryotic cells when they are exposed to stress. by increasing their hsp content, cells protect themselves from lethal assaults, primarily because hsp interfere with the uncontrolled protein unfolding that occurs under stress. however, hsp are not produced only by stressed cells; some hsp are synthesized constitutively and perform important housekeeping functions. accordingly, hsp are involved in the assembly of molecule ... | 1999 | 9880473 |
| differential stabilities of phosphorylated response regulator domains reflect functional roles of the yeast osmoregulatory sln1 and ssk1 proteins. | osmoregulation in saccharomyces cerevisiae involves a multistep phosphorelay system requiring three proteins, sln1, ypd1, and ssk1, that are related to bacterial two-component signaling proteins, in particular, those involved in regulating sporulation in bacillus subtilis and anaerobic respiration in escherichia coli. the sln1-ypd1-ssk1 phosphorelay regulates a downstream mitogen-activated protein kinase cascade which ultimately controls the concentration of glycerol within the cell under hypero ... | 1999 | 9882653 |
| [experimental study of the relationship between bordetella pertussis and b. parapertussis infections in suckling mice]. | bordetella parapertussis can occasionally be isolated in the late period of epidemic pertussis and even from the same patient infected with b. pertussis, thereby closely related to b. pertussis. compared with b. pertussis, it is more frequently isolated from vaccinated individuals as well. based on the findings, we carried out an experimental study to establish their interrelationship in mice infected with b. parapertussis alone or with both bacteria. the total of 4 groups, each of which constit ... | 1998 | 9884503 |
| quantification of bordetella pertussis in clinical samples by colorimetric detection of competitive pcr products. | quantification of microorganisms is an important part of the normal diagnostic work of a clinical microbiology laboratory. traditionally the diagnosis of pertussis is subject to a yes or no approach with no quantitative dimension. this can, however, be of interest as a factor when judging the risk of a patient spreading the bacterium and as a research tool. the aim of the present study was to develop a pcr-based quantitative assay for bordetella pertussis dna in clinical nasopharyngeal aspirates ... | 1998 | 9890265 |
| the evolutionary origin of the protein-translocating channel of chloroplastic envelope membranes: identification of a cyanobacterial homolog. | the known envelope membrane proteins of the chloroplastic protein import apparatus lack sequence similarity to proteins of other eukaryotic or prokaryotic protein transport systems. however, we detected a putative homolog of the gene encoding toc75, the protein-translocating channel from the outer envelope membrane of pea chloroplasts, in the genome of the cyanobacterium synechocystis sp. pcc 6803. we investigated whether the low sequence identity of 21% reflects a structural and functional rela ... | 1999 | 9892711 |
| expression of bvgas of bordetella pertussis represses flagellar biosynthesis of escherichia coli. | bvgas is a two-component system of bordetella pertussis involved in the reciprocal regulation of the virulence genes and the flagellar biosynthesis. in this study, we found that expression of bvgas in escherichia coli also results in reduced motility. the repression was relieved by the addition of known chemical modulators of bvgas such as mgso4 and nicotinic acid, indicating that functional bvgas proteins are required for the negative control of e. coli motility. in addition, bvgas repressed th ... | 1999 | 9914310 |
| vaccination against anthrax with attenuated recombinant strains of bacillus anthracis that produce protective antigen. | the protective efficacy of several live, recombinant anthrax vaccines given in a single-dose regimen was assessed with hartley guinea pigs. these live vaccines were created by transforming deltaanr and deltasterne, two nonencapsulated, nontoxinogenic strains of bacillus anthracis, with four different recombinant plasmids that express the anthrax protective antigen (pa) protein to various degrees. this enabled us to assess the effect of the chromosomal background of the strain, as well as the amo ... | 1999 | 9916059 |
| intracellular delivery of a cytolytic t-lymphocyte epitope peptide by pertussis toxin to major histocompatibility complex class i without involvement of the cytosolic class i antigen processing pathway. | a cd8(+) cytolytic t-lymphocyte (ctl) response to antigen-presenting cells generally requires intracellular delivery or synthesis of antigens in order to access the major histocompatibility complex (mhc) class i processing and presentation pathway. to test the ability of pertussis toxin (pt) to deliver peptides to the class i pathway for ctl recognition, we constructed fusions of ctl epitope peptides with a genetically detoxified derivative of pt (pt9k/129g). two sites on the a (s1) subunit of p ... | 1999 | 9916065 |
| a controlled clinical study of the effect of nasal immunization with a streptococcus mutans antigen alone or incorporated into liposomes on induction of immune responses. | recent attention to mucosal immunization strategies has been focused on the nasal route for vaccine delivery. this study was designed to determine the effectiveness of a liposome-protein vaccine compared to that of a protein-only vaccine in inducing immune responses in humans. healthy subjects were randomly assigned to two groups and immunized intranasally with a crude antigen preparation rich in glucosyltransferase (c-gtf) from streptococcus mutans, alone or in liposomes. parotid saliva, nasal ... | 1999 | 9916067 |
| characterization of candidate live oral salmonella typhi vaccine strains harboring defined mutations in aroa, aroc, and htra. | the properties of two candidate salmonella typhi-based live oral typhoid vaccine strains, brd691 (s. typhi ty2 harboring mutations in aroa and aroc) and brd1116 (s. typhi ty2 harboring mutations in aroa, aroc, and htra), were compared in a number of in vitro and in vivo assays. brd1116 exhibited an increased susceptibility to oxidative stress compared with brd691, but both strains were equally resistant to heat shock. both strains showed a similar ability to invade caco-2 and ht-29 epithelial ce ... | 1999 | 9916080 |
| identification and characterization of ptlc, an essential component of the pertussis toxin secretion system. | ptlc is a member of a set of proteins necessary for the secretion of pertussis toxin (pt) from bordetella pertussis. using polyclonal antibodies specific for ptlc, we identified ptlc as a protein with an apparent molecular weight of 85,000 that localizes to the membrane fraction of bacterial cell extracts. we found that a mutant strain of b. pertussis that contains an in-frame deletion in ptlc is unable to secrete pt and that pt secretion is fully restored by expressing ptlc in trans, indicating ... | 1999 | 9916087 |
| cytotoxic action of serratia marcescens hemolysin on human epithelial cells. | incubation of human epithelial cells with nanomolar concentrations of chromatographically purified serratia marcescens hemolysin (shla) caused irreversible vacuolation and subsequent lysis of the cells. vacuolation differed from vacuole formation by helicobacter pylori vaca. sublytic doses of shla led to a reversible depletion of intracellular atp. restoration to the initial atp level was presumably due to the repair of the toxin damage and was inhibited by cycloheximide. pores formed in epithel ... | 1999 | 9916096 |
| characterization of a waaf (rfaf) homolog expressed by haemophilus ducreyi. | haemophilus ducreyi lipooligosaccharide (los) is capable of inducing an inflammatory response in skin (a. a. campagnari, l. m. wild, g. griffiths, r. j. karalus, m. a. wirth, and s. m. spinola, infect. immun. 59:2601-2608, 1991) and likely contributes to the virulence of this sexually transmitted pathogen (b. a. bauer, m. k. stevens, and e. j. hansen, infect. immun. 68:4290-4298, 1998). an open reading frame in h. ducreyi 35000 was found to encode a predicted protein that was 59% identical to th ... | 1999 | 9916106 |
| quantification of bacterial lipopolysaccharides by the purpald assay: measuring formaldehyde generated from 2-keto-3-deoxyoctonate and heptose at the inner core by periodate oxidation. | we have adapted the purpald assay (m. s. quesenberry and y. c. lee, anal. biochem. 234, 50-55, 1996) to quantify lipopolysaccharide (lps) content in solution in 96-well microtiter plates at room temperature. this method employs the oxidation of unsubstituted terminal vicinal glycol groups in 2-keto-3-deoxyoctonate (kdo) and l-(or d-)glycero-d-manno-heptose of lps molecules by periodate to release formaldehyde. the formaldehyde is quantified at 550 nm (or 530-570 nm) by reacting with purpald reag ... | 1999 | 9918668 |
| [comparative analysis of bordetella pertussis strains isolated from patients in years 1995-1998 and in 1968]. | 1998 | 9919931 | |
| time-course of infection and responses in a coughing rat model of pertussis. | adult female sprague-dawley rats were challenged intrabronchially with bordetella pertussis strain 18-323 embedded in fine agarose beads and the time-course of infection and other events was determined. there was a steady decline in the numbers of b. pertussis recovered from the rat lungs, with clearance of the infection in most animals by day 12. leucocytosis, lung inflammation and an increase in total serum ige in the rats as a result of the challenge were highest around day 10, which was coin ... | 1999 | 9920131 |
| a putative adhesin gene cloned from campylobacter jejuni. | thirteen campylobacter jejuni strains of human origin showed differing behaviours when analysed for their ability to bind the caco-2 cell line in vitro, suggesting variations in genetic complements and/or regulation. we designed an oligonucleotide probe corresponding to a highly conserved part of adhesins from various gram-negative bacteria. among our laboratory collection, southern hybridization has demonstrated that only a discrete number of strains harbour this sequence. the corresponding gen ... | 1998 | 9921579 |
| immunochemical analysis of ump kinase from escherichia coli. | mono- and polyclonal antibodies directed against ump kinase from escherichia coli were tested with the intact protein or with fragments obtained by deletion mutagenesis. as detected in enzyme-linked immunosorbent assay tests, the carboxy-terminal quarter of ump kinase is immunodominant. polyclonal antibodies inhibited the enzyme activity with partial or total loss of allosteric effects exerted by utp and gtp, respectively. these data indicate that the utp and gtp binding sites in ump kinase are ... | 1999 | 9922246 |
| phaf, a polyhydroxyalkanoate-granule-associated protein of pseudomonas oleovorans gpo1 involved in the regulatory expression system for pha genes. | the phac1 gene codes for the medium-chain-length polyhydroxyalkanoate (mcl pha) synthase of pseudomonas oleovorans gpo1, which produces mcl pha when grown in an excess of carbon source and under nitrogen limitation. in this work, we have demonstrated, by constructing a recombinant p. oleovorans strain carrying a phac1::lacz reporter system, that the phac1 gene is expressed efficiently in the presence of octanoic acid while its expression is repressed when glucose or citrate is used as the carbon ... | 1999 | 9922249 |
| sequence and function of luxu: a two-component phosphorelay protein that regulates quorum sensing in vibrio harveyi. | vibrio harveyi regulates the expression of bioluminescence (lux) in response to cell density, a phenomenon known as quorum sensing. in v. harveyi, two independent quorum-sensing systems exist, and each produces, detects, and responds to a specific cell density-dependent autoinducer signal. the autoinducers are recognized by two-component hybrid sensor kinases called luxn and luxq, and sensory information from both systems is transduced by a phosphorelay mechanism to the response regulator protei ... | 1999 | 9922254 |
| identification of a vibrio cholerae rtx toxin gene cluster that is tightly linked to the cholera toxin prophage. | we identify and characterize a gene cluster in el tor vibrio cholerae that encodes a cytotoxic activity for hep-2 cells in vitro. this gene cluster contains four genes and is physically linked to the cholera toxin (ctx) element in the v. cholerae genome. we demonstrate by using insertional mutagenesis that this gene cluster is required for the cytotoxic activity. the toxin, rtxa, resembles members of the rtx (repeats in toxin) toxin family in that it contains a gd-rich repeated motif. like other ... | 1999 | 9927695 |
| activation of nitric oxide release and oxidative metabolism by leukotrienes b4, c4, and d4 in human polymorphonuclear leukocytes. | because arachidonate metabolites are potent mediators of inflammation, we have studied the effects of leukotriene b4 (ltb4) and the cysteinyl leukotrienes c4 and d4 (ltc4 and ltd4) on the release of nitric oxide (no), in vitro, by human polymorphonuclear granulocytes (pmn). two independent and highly sensitive real-time methods were used for these studies, ie, the no-dependent oxidation of oxyhemoglobin (hbo2) to methemoglobin and a no-sensitive microelectrode. when activated with ltb4, ltc4, or ... | 1999 | 9949184 |
| bacterial adhesins: common themes and variations in architecture and assembly. | 1999 | 9973330 | |
| analysis of rpos mrna in salmonella dublin: identification of multiple transcripts with growth-phase-dependent variation in transcript stability. | in salmonella dublin, rpos encodes an alternative sigma factor of the rna polymerase that activates a variety of stationary-phase-induced genes, including some virulence-associated genes. in this work, we studied the regulation and transcriptional organization of rpos during growth. we found two transcripts, 2.3 and 1.6 kb in length, that represent the complete rpos sequence. the 2.3-kb transcript is a polycistronic message that also includes the upstream nlpd gene. it is driven by a weak promot ... | 1999 | 9973354 |
| direct delivery of the bordetella pertussis adenylate cyclase toxin to the mhc class i antigen presentation pathway. | among bacterial toxins, the adenylate cyclase toxin of bordetella pertussis (cyaa) has a unique mechanism of entry that consists in the direct translocation of its catalytic domain across the plasma membrane of target cell, a mechanism supposed to be independent of any endocytic pathway. here, we report that the cyaa toxin is delivered to the cytosolic pathway for mhc class i-restricted ag presentation. using peritoneal macrophages as apc, we show that the ova 257-264 cd8+ epitope genetically in ... | 1999 | 9973458 |
| nested duplex pcr to detect bordetella pertussis and bordetella parapertussis and its application in diagnosis of pertussis in nonmetropolitan southeast queensland, australia. | a duplex pcr to detect bordetella pertussis and bordetella parapertussis was developed with the insertion sequences is481 (b. pertussis) and is1001 (b. parapertussis) and evaluated with specimens from 520 consecutive patients presenting with possible pertussis. no culture-positive-pcr-negative results occurred, giving the method a sensitivity of 100%. for b. pertussis, 58 of 520 patients (11.2%) were positive by pcr compared to 17 of 520 patients positive (3.3%) by culture. for b. parapertussis, ... | 1999 | 9986820 |
| the structural and functional organization of h-ns-like proteins is evolutionarily conserved in gram-negative bacteria. | the structural gene of the h-ns protein, a global regulator of bacterial metabolism, has been identified in the group of enterobacteria as well as in closely related bacteria, such as erwinia chrysanthemi and haemophilus influenzae. isolated outside these groups, the bph3 protein of bordetella pertussis exhibits a low amino acid conservation with h-ns, particularly in the n-terminal domain. to obtain information on the structure, function and/or evolution of h-ns, we searched for other h-ns-rela ... | 1999 | 9987132 |
| characterization of the c-terminal domain essential for toxic activity of adenylate cyclase toxin. | adenylate cyclase toxin (cyaa) of bordetella pertussis belongs to the rtx family of toxins. these toxins are characterized by a series of glycine- and aspartaterich nonapeptide repeats located at the c-terminal half of the toxin molecules. for activity, rtx toxins require ca2+, which is bound through the repeat region. here, we identified a stretch of 15 amino acids (block a) that is located c-terminally to the repeat and is essential for the toxic activity of cyaa. block a is required for the i ... | 1999 | 9987138 |
| role of antibodies against bordetella pertussis virulence factors in adherence of bordetella pertussis and bordetella parapertussis to human bronchial epithelial cells. | immunization with whole-cell pertussis vaccines (wcv) containing heat-killed bordetella pertussis cells and with acellular vaccines containing genetically or chemically detoxified pertussis toxin (pt) in combination with filamentous hemagglutinin (fha), pertactin (prn), or fimbriae confers protection in humans and animals against b. pertussis infection. in an earlier study we demonstrated that fha is involved in the adherence of these bacteria to human bronchial epithelial cells. in the present ... | 1999 | 10024542 |
| role of bordetella pertussis virulence factors in adherence to epithelial cell lines derived from the human respiratory tract. | during colonization of the respiratory tract by bordetella pertussis, virulence factors contribute to adherence of the bacterium to the respiratory tract epithelium. in the present study, we examined the roles of the virulence factors filamentous hemagglutinin (fha), fimbriae, pertactin (prn), and pertussis toxin (pt) in the adherence of b. pertussis to cells of the human bronchial epithelial cell line nci-h292 and of the laryngeal epithelial cell line hep-2. using b. pertussis mutant strains an ... | 1999 | 10024543 |
| transcutaneous immunization with bacterial adp-ribosylating exotoxins as antigens and adjuvants. | transcutaneous immunization (tci) is a new technique that uses the application of vaccine antigens in a solution on the skin to induce potent antibody responses without systemic or local toxicity. we have previously shown that cholera toxin (ct), a potent adjuvant for oral and nasal immunization, can induce both serum and mucosal immunoglobulin g (igg) and iga and protect against toxin-mediated mucosal disease when administered by the transcutaneous route. additionally, ct acts as an adjuvant fo ... | 1999 | 10024549 |
| a 55-kilodalton immunodominant antigen of porphyromonas gingivalis w50 has arisen via horizontal gene transfer. | a 55-kda outer membrane protein of porphyromonas gingivalis w50 is a significant target of the serum immunoglobulin g antibody response of periodontal disease patients and hence may play an important role in host-bacterium interactions in periodontal disease. the gene encoding the 55-kda antigen (ragb, for receptor antigen b) was isolated on a 9.5-kb partial sau3ai fragment of p. gingivalis w50 chromosomal dna in puc18 by immunoscreening with a monoclonal antibody to this antigen. the 1.6-kb ope ... | 1999 | 10024556 |
| linear peptide specificity of bovine antibody responses to p67 of theileria parva and sequence diversity of sporozoite-neutralizing epitopes: implications for a vaccine. | a stage-specific surface antigen of theileria parva, p67, is the basis for the development of an anti-sporozoite vaccine for the control of east coast fever (ecf) in cattle. by pepscan analysis with a series of overlapping synthetic p67 peptides, the antigen was shown to contain five distinct linear peptide sequences recognized by sporozoite-neutralizing murine monoclonal antibodies. three epitopes were located between amino acid positions 105 to 229 and two were located between positions 617 to ... | 1999 | 10024569 |
| the levels and bactericidal capacity of antibodies directed against the uspa1 and uspa2 outer membrane proteins of moraxella (branhamella) catarrhalis in adults and children. | the uspa1 and uspa2 proteins from moraxella catarrhalis share antigenic epitopes and are promising vaccine candidates. in this study, the levels and bactericidal activities of antibodies in sera from healthy adults and children toward uspa1 and uspa2 from the o35e strain were measured. human sera contained antibodies to both proteins, and the levels of immunoglobulin g (igg) antibodies were age dependent. adult sera had significantly higher titers of igg than child sera (p < 0.01). the igg3 tite ... | 1999 | 10024576 |
| characterization of human bactericidal antibodies to bordetella pertussis. | the bordetella pertussis brka protein protects against the bactericidal activity of complement and antibody; however, some individuals mount an immune response that overcomes this bacterial defense. to further characterize this process, the bactericidal activities of sera from 13 adults with different modes of exposure to b. pertussis (infected as adults, occupational exposure, immunized with an acellular vaccine, or no identified exposure) against a wild-type strain and a brka complement-sensit ... | 1999 | 10024590 |
| probing the function of bordetella bronchiseptica adenylate cyclase toxin by manipulating host immunity. | we have examined the role of adenylate cyclase-hemolysin (cyaa) by constructing an in-frame deletion in the bordetella bronchiseptica cyaa structural gene and comparing wild-type and cyaa deletion strains in natural host infection models. both the wild-type strain rb50 and its adenylate cyclase toxin deletion (deltacyaa) derivative efficiently establish persistent infections in rabbits, rats, and mice following low-dose inoculation. in contrast, an inoculation protocol that seeds the lower respi ... | 1999 | 10024599 |
| surface expression of a protective recombinant pertussis toxin s1 subunit fragment in streptococcus gordonii. | in this study, the expression of the bordetella pertussis s1 subunit was tested in streptococcus gordonii, a commensal oral bacterium which has the potential to be a live oral vaccine vehicle. the dna fragment encoding the n-terminal 179 amino acids of the s1 subunit was ligated into the middle part of spap, the surface protein antigen p1 gene originating from streptococcus mutans. the resulting construct, carried on the escherichia coli-streptococcus shuttle vector pdl276, was introduced into s ... | 1999 | 10024603 |
| the effect of cigarette smoke on adherence of respiratory pathogens to buccal epithelial cells. | smoking is associated with an increased risk of respiratory tract infection in adults. in children, exposure to cigarette smoke is a risk factor for respiratory tract infection and bacterial meningitis: active smoking and passive exposure to cigarette smoke is also associated with carriage of some potentially pathogenic species of bacteria in both adults and children. the aims of the study were to determine the effect of active smoking on: (1) bacterial binding to epithelial cells; (2) expressio ... | 1999 | 10030544 |
| the vitronectin receptor and its associated cd47 molecule mediates proinflammatory cytokine synthesis in human monocytes by interaction with soluble cd23. | the vitronectin receptor, alphavbeta3 integrin, plays an important role in tumor cell invasion, angiogenesis, and phagocytosis of apoptotic cells. cd47, a member of the multispan transmembrane receptor family, physically and functionally associates with vitronectin receptor (vnr). although vitronectin (vn) is not a ligand of cd47, anti-cd47 and beta3 mabs suppress vn, but not fibronectin (fn) binding and function. here, we show that anti-cd47, anti-beta3 mab and vn, but not fn, inhibit scd23-med ... | 1999 | 10037797 |
| efflux-mediated aminoglycoside and macrolide resistance in burkholderia pseudomallei. | burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to a wide range of antimicrobial agents including beta-lactams, aminoglycosides, macrolides, and polymyxins. we used tn5-ot182 to mutagenize b. pseudomallei to identify the genes involved in aminoglycoside resistance. we report here on the identification of amrab-opra, a multidrug efflux system in b. pseudomallei which is specific for both aminoglycoside and macrolide antibiotics. we isolated two transposon ... | 1999 | 10049252 |
| complete sequence of a 184-kilobase catabolic plasmid from sphingomonas aromaticivorans f199. | the complete 184,457-bp sequence of the aromatic catabolic plasmid, pnl1, from sphingomonas aromaticivorans f199 has been determined. a total of 186 open reading frames (orfs) are predicted to encode proteins, of which 79 are likely directly associated with catabolism or transport of aromatic compounds. genes that encode enzymes associated with the degradation of biphenyl, naphthalene, m-xylene, and p-cresol are predicted to be distributed among 15 gene clusters. the unusual coclustering of gene ... | 1999 | 10049392 |
| gi protein modulation induced by a selective inverse agonist for the peripheral cannabinoid receptor cb2: implication for intracellular signalization cross-regulation. | the peripheral cannabinoid receptor (cb2) is a g protein-coupled receptor that is both positively and negatively coupled to the mitogen-activated protein kinase (mapk) and camp pathways, respectively, through a bordetella pertussis toxin-sensitive g protein. cb2 receptor-transfected chinese hamster ovary cells exhibit high constitutive activity blocked by the cb2-selective ligand, sr 144528, working as an inverse agonist. we showed here that in addition to the inhibition of autoactivated cb2 in ... | 1999 | 10051530 |
| localization of non-mhc collagen-induced arthritis susceptibility loci in dba/1j mice. | one approach to understanding common human diseases is to determine the genetic defects responsible for similar diseases in animal models and place those defective genes in their corresponding biochemical pathways. our laboratory is working with an animal model for human rheumatoid arthritis called collagen-induced arthritis (cia). we are particularly interested in determining the location of disease-predisposing loci. to that end, we performed experiments to localize susceptibility loci for cia ... | 1999 | 10051620 |
| surface proteins of gram-positive bacteria and mechanisms of their targeting to the cell wall envelope. | the cell wall envelope of gram-positive bacteria is a macromolecular, exoskeletal organelle that is assembled and turned over at designated sites. the cell wall also functions as a surface organelle that allows gram-positive pathogens to interact with their environment, in particular the tissues of the infected host. all of these functions require that surface proteins and enzymes be properly targeted to the cell wall envelope. two basic mechanisms, cell wall sorting and targeting, have been ide ... | 1999 | 10066836 |
| temporal trends in the population structure of bordetella pertussis during 1949-1996 in a highly vaccinated population. | the population structure of bordetella pertussis in the netherlands in 5 successive periods, encompassing 1949-1996, was analyzed by dna typing ("fingerprinting"). in 10 years following the introduction of wide-scale vaccination in 1953, a decrease in genotypic diversity (gd) was observed, suggesting clonal expansion of strains that were adapted to vaccine-induced immunity. in subsequent periods, gd increased to prevaccination levels, probably reflecting a gradual adaptation of the b. pertussis ... | 1999 | 10068587 |
| rat liver gtp-binding proteins mediate changes in mitochondrial membrane potential and organelle fusion. | the variety of mitochondrial morphology in healthy and diseased cells can be explained by regulated mitochondrial fusion. previously, a mitochondrial outer membrane fraction containing fusogenic, aluminum fluoride (alf4)-sensitive gtp-binding proteins (mtg) was separated from rat liver (j. d. cortese, exp. cell res. 240: 122-133, 1998). quantitative confocal microscopy now reveals that mtg transiently increases mitochondrial membrane potential (deltapsi) when added to permeabilized rat hepatocyt ... | 1999 | 10069988 |
| identification of the tlidef abc transporter specific for lipase in pseudomonas fluorescens sik w1. | pseudomonas fluorescens, a gram-negative psychrotrophic bacterium, secretes a thermostable lipase into the extracellular medium. in our previous study, the lipase of p. fluorescens sik w1 was cloned and expressed in escherichia coli, but it accumulated as inactive inclusion bodies. amino acid sequence analysis of the lipase revealed a potential c-terminal targeting sequence recognized by the atp-binding cassette (abc) transporter. the genetic loci around the lipase gene were searched, and a secr ... | 1999 | 10074078 |
| analysis with a combination of macrorestriction endonucleases reveals a high degree of polymorphism among bordetella pertussis isolates in eastern france. | from 1990 to 1996, routine screening for whooping cough identified 399 patients with a calmodulin-dependent adenylate cyclase-positive test result and yielded 69 bordetella pertussis isolates. none of the patients were fully vaccinated, and most were less than 6 months old. analysis of total dna by pulsed-field gel electrophoresis (pfge) after xbai, spei, or drai macrorestriction yielded 19, 15, and 5 different patterns, respectively, whereas ribotyping failed to demonstrate any strain polymorph ... | 1999 | 10074527 |
| an aerosol challenge model of bordetella pertussis infection as a potential bioassay for acellular pertussis vaccines. | whole cell and five different types of acellular pertussis vaccine were assayed using a mouse aerosol challenge model which permitted delivery of a controlled, consistent dose of bordetella pertussis to the lower respiratory tract. using this system, the viable counts in the lungs of vaccinated mice were immunisation dose-dependent and allowed the protective capacity of different vaccine preparations to be distinguished. this model may thus provide the basis for a protection assay for pertussis ... | 1999 | 10075163 |
| identification of bordetella pertussis virulence-associated outer membrane proteins. | bordetella pertussis virulence-associated 30-, 32-, 90- and 95-kda outer membrane proteins were purified and their n-terminal amino acid sequences were determined. the 30- and 32-kda outer membrane proteins showed identity to the c-terminal region of the precursors of the serum resistance protein (brka) and the tracheal colonization factor, respectively. we confirmed the cleavage site of these precursors after n731 for brka and after n393 for tracheal colonization factor. associated with the 32- ... | 1999 | 10079522 |
| simultaneous amplification of bordetella repeated insertion sequences and toxin promoter region gene by polymerase chain reaction. | a polymerase chain reaction was devised to simultaneously detect repeated insertion sequences and the pertussis toxin promoter gene for the diagnostic identification of bordetella pertussis, b. parapertussis, and b. bronchiseptica. the sensitivity of this method was sufficient to detect one b. pertussis organism using the following cycles and temperatures: 95 degrees c for 15 min, followed by 32 amplification cycles (1 min at 95 degrees c, 1 min at 66 degrees c, 1 min at 72 degrees c), and final ... | 1999 | 10084330 |
| the alternative sigma factor, sigmae, is critically important for the virulence of salmonella typhimurium. | in escherichia coli, extracytoplasmic stress is partially controlled by the alternative sigma factor, rpoe (sigmae). in response to environmental stress or alteration in the protein content of the cell envelope, sigmae upregulates the expression of a number of genes, including htra. it has been shown that htra is required for intramacrophage survival and virulence in salmonella typhimurium. to investigate whether sigmae-regulated genes other than htra are involved in salmonella virulence, we ina ... | 1999 | 10084987 |
| in vivo expression and immunoadjuvancy of a mutant of heat-labile enterotoxin of escherichia coli in vaccine and vector strains of vibrio cholerae. | vibrio cholerae secretes cholera toxin (ct) and the closely related heat-labile enterotoxin (lt) of escherichia coli, the latter when expressed in v. cholerae. both toxins are also potent immunoadjuvants. mutant lt molecules that retain immunoadjuvant properties while possessing markedly diminished enterotoxic activities when expressed by e. coli have been developed. one such mutant lt molecule has the substitution of a glycine residue for arginine-192 [lt(r192g)]. live attenuated strains of v. ... | 1999 | 10085006 |
| oligomerization of anthrax toxin protective antigen and binding of lethal factor during endocytic uptake into mammalian cells. | the protective antigen (pa) protein of anthrax toxin binds to a cellular receptor and is cleaved by cell surface furin to produce a 63-kda fragment (pa63). the receptor-bound pa63 oligomerizes to a heptamer and acts to translocate the catalytic moieties of the toxin, lethal factor (lf) and edema factor (ef), from endosomes to the cytosol. in this report, we used nondenaturing gel electrophoresis to show that each pa63 subunit in the heptamer can bind one lf molecule. studies using pa immobilized ... | 1999 | 10085027 |
| identification of a receptor-binding region within domain 4 of the protective antigen component of anthrax toxin. | anthrax toxin from bacillus anthracis is a three-component toxin consisting of lethal factor (lf), edema factor (ef), and protective antigen (pa). lf and ef are the catalytic components of the toxin, whereas pa is the receptor-binding component. to identify residues of pa that are involved in interaction with the cellular receptor, two solvent-exposed loops of domain 4 of pa (amino acids [aa] 679 to 693 and 704 to 723) were mutagenized, and the altered proteins purified and tested for toxicity i ... | 1999 | 10085028 |
| an epidemic of a pertussis-like illness caused by chlamydia pneumoniae. | between june and july, 1994, we encountered an epidemic of a pertussis-like illness in adolescents in a junior high school located in a rural area of japan. the purposes of this study were to record the clinical manifestations and to identify an etiology. | 1999 | 10093951 |
| the major phase-variable outer membrane protein of escherichia coli structurally resembles the immunoglobulin a1 protease class of exported protein and is regulated by a novel mechanism involving dam and oxyr. | here we report the characterization of an escherichia coli gene (agn43) which encodes the principal phase-variable outer membrane protein termed antigen 43 (ag43). the agn43 gene encodes a precursor protein of 107 kda containing a 52-amino-acid signal sequence. posttranslational processing generates an alpha43 subunit (predicted mr of 49,789) and a c-terminal domain (beta43) with features typical of a bacterial integral outer membrane protein (predicted mr of 51, 642). secondary structure analys ... | 1999 | 10094691 |
| spontaneous regression of primary autoreactivity during chronic progression of experimental autoimmune encephalomyelitis and multiple sclerosis. | experimental autoimmune encephalomyelitis (eae) is a widely used animal model for multiple sclerosis (ms). eae is typically initiated by cd4(+) t helper cell type 1 (th1) autoreactivity directed against a single priming immunodominant myelin peptide determinant. recent studies have shown that clinical progression of eae involves the accumulation of neo-autoreactivity, commonly referred to as epitope spreading, directed against peptide determinants not involved in the priming process. this study ... | 1999 | 10190894 |
| effect of aspergillus terreus mycotoxins on nitric oxide synthase activity in human erythroid k-562 cells. | because several stimuli of microbial origin enhance the activity of nitric oxide synthase (nos) in human cells of the myeloid lineage, we decided to investigate whether cellular damage induced by aspergillus terreus mycotoxins could be associated with an increase in nos activity. a pool of mycotoxins rather than individual toxins was tested so that the natural conditions could be mimicked. in the present study, we report that a crude extract of a. terreus induces cellular damage and increases no ... | 1999 | 10191507 |
| cell-specific coupling of pge2 to different transduction pathways in arginine vasopressin- and glucagon-sensitive segments of the rat renal tubule. | 1. the aim of the present study was to investigate the transduction pathways elicited by prostaglandin e2 (pge2) to inhibit hormone-stimulated adenosine 3':5'-cyclic monophosphate (cyclic amp) accumulation in the outer medullary collecting duct (omcd) and medullary thick ascending limb (mtal) microdissected from the rat nephron. 2. in the omcd, 0.3 microm pge2 and low concentrations of ca2+ ionophores (10 nm ionomycin or 50 nm a23187) inhibited by about 50% a same pool of arginine vasopressin (a ... | 1999 | 10193786 |
| the conserved lysine 860 in the additional fatty-acylation site of bordetella pertussis adenylate cyclase is crucial for toxin function independently of its acylation status. | the bordetella pertussis rtx (repeat in toxin family protein) adenylate cyclase toxin-hemolysin (act) acquires biological activity upon a single amide-linked palmitoylation of the epsilon-amino group of lysine 983 (lys983) by the accessory fatty-acyltransferase cyac. however, an additional conserved rtx acylation site can be identified in act at lysine 860 (lys860), and this residue becomes palmitoylated when recombinant act (r-ec-act) is produced together with cyac in escherichia coli k12. we h ... | 1999 | 10196151 |
| the ctra response regulator mediates temporal control of gene expression during the caulobacter cell cycle. | in its role as a global response regulator, ctra controls the transcription of a diverse group of genes at different times in the caulobacter crescentus cell cycle. to understand the differential regulation of ctra-controlled genes, we compared the expression of two of these genes, the fliq flagellar gene and the ccrm dna methyltransferase gene. despite their similar promoter architecture, these genes are transcribed at different times in the cell cycle. pfliq is activated earlier than pccrm. ph ... | 1999 | 10198005 |
| cloning and characterization of two bistructural s-layer-rtx proteins from campylobacter rectus. | campylobacter rectus is an important periodontal pathogen in humans. a surface-layer (s-layer) protein and a cytotoxic activity have been characterized and are thought to be its major virulence factors. the cytotoxic activity was suggested to be due to a pore-forming protein toxin belonging to the rtx (repeats in the structural toxins) family. in the present work, two closely related genes, csxa and csxb (for c. rectus s-layer and rtx protein) were cloned from c. rectus and characterized. the cs ... | 1999 | 10198015 |
| bordetella pertussis waaa encodes a monofunctional 2-keto-3-deoxy-d-manno-octulosonic acid transferase that can complement an escherichia coli waaa mutation. | bordetella pertussis lipopolysaccharide (lps) contains a single 2-keto-3-deoxy-d-manno-octulosonic acid (kdo) residue, whereas lps from escherichia coli contains at least two. here we report that b. pertussis waaa encodes an enzyme capable of transferring only a single kdo during the biosynthesis of lps and that this activity is sufficient to complement an e. coli waaa mutation. | 1999 | 10198035 |