Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| pcr assay or culture for diagnosis of bordetella pertussis in the routine diagnostic laboratory? | a nested pcr method was compared with culture for the detection of bordetella pertussis in a routine clinical diagnostic laboratory. a total of 241 clinical nasopharyngeal aspirates were examined in parallel in the laboratory. both methods were positive for 75 samples (31%), eight samples were positive by nested pcr only (3.3%), and one sample was positive by culture only (0.4%). the mean time actually required in the clinical laboratory (not operating with pertussis diagnosis during weekends) f ... | 1997 | 9459391 |
| host cell killing and bacterial conjugation require overlapping sets of genes within a 22-kb region of the legionella pneumophila genome. | a 22-kb dna locus of legionella pneumophila is described that contains 18 genes, 16 of which are required for macrophage killing (icm genes). in this paper two previously described icm loci were linked by the discovery of five genes located between the two loci. four of the newly described genes are required for macrophage killing (icmmlke) and one is dispensable. the 16 icm genes appeared to be organized as six individual genes (icmr, icmq, icmg, icmc, icmd, and icmf), and four operons (icmts, ... | 1998 | 9465074 |
| transcriptional analysis of the bordetella alcaligin siderophore biosynthesis operon. | the alc gene cluster of bordetella pertussis includes three genes, alca, alcb, and alcc, which are involved in alcaligin siderophore biosynthesis in response to iron starvation. the production of alca, alcb, and alcc in bordetella cells and the transcriptional organization of alca, alcb, and alcc were investigated by using a set of three alc'-'lacz gene fusion constructs that were contiguous with the known promoter upstream of alca and extended to fusion junctions within each alc cistron. all th ... | 1998 | 9473039 |
| identification and characterization of alcr, a gene encoding an arac-like regulator of alcaligin siderophore biosynthesis and transport in bordetella pertussis and bordetella bronchiseptica. | a bordetella bronchiseptica iron transport mutant was isolated following an enrichment procedure based on streptonigrin resistance. the mutant displayed a growth defect on iron-restricted medium containing ferric alcaligin as the sole iron source. in addition to the apparent inability to acquire iron from the siderophore, the mutant failed to produce alcaligin as well as two known iron-regulated proteins, one of which is the alcc alcaligin biosynthesis protein. a 1.6-kb kpni-psti bordetella pert ... | 1998 | 9473040 |
| identification of alcr, an arac-type regulator of alcaligin siderophore synthesis in bordetella bronchiseptica and bordetella pertussis. | a fur titration assay was used to isolate dna fragments bearing putative fur binding sites (fbs) from a partial bordetella bronchiseptica genomic dna library. a recombinant plasmid bearing a 3.5-kb dna insert was further studied. successive deletions in the cloned fragment enabled us to map a putative fbs at about 2 kb from one end. sequence analysis revealed the presence of an fbs upstream from a new gene encoding an arac-type transcriptional regulator. the deduced protein displays similarity t ... | 1998 | 9473041 |
| the stpa protein functions as a molecular adapter to mediate repression of the bgl operon by truncated h-ns in escherichia coli. | the mechanism of repression of the beta-glucoside utilization (bgl) operon of escherichia coli by a carboxy-terminally truncated derivative of the nucleoid-associated protein h-ns which is defective in dna binding was investigated. the dna-binding function of the h-ns-like protein stpa was found to be necessary for repression, which is consistent with a role for stpa as a dna-binding adapter for mutant derivatives of h-ns. | 1998 | 9473058 |
| monokine production following in vitro stimulation of the thp-1 human monocytic cell line with pertussis vaccine components. | whole-cell pertussis found in diphtheria-tetanus-pertussis (dtp) vaccine can produce symptoms reminiscent of biological responses to circulating proinflammatory monokines such as il-6, il-1beta, and tnfalpha. therefore the ability of pertussis-containing vaccines and several heat-killed bordetella pertussis preparations to stimulate cytokine production in a human monocytic cell line, thp-1, were examined. the whole-cell pertussis vaccine induced significantly more il-6, il-1beta, and tnfalpha pr ... | 1998 | 9475357 |
| compartmentalization of t cell responses following respiratory infection with bordetella pertussis: hyporesponsiveness of lung t cells is associated with modulated expression of the co-stimulatory molecule cd28. | we have used a murine respiratory challenge model to examine the local t cell responses in the lung during infection with bordetella pertussis. t cells from lung parenchyma and airways of naive and infected mice were refractory to both antigen and mitogen stimulation in the presence of lung macrophages. furthermore irradiated mononuclear cells from the lungs suppressed antigen and mitogen-induced proliferation, but not ifn-gamma production, by splenic t cells. removal of macrophages and stimulat ... | 1998 | 9485195 |
| th1/th2 cytokine responses following hiv-1 immunization in seronegative volunteers. the aids vaccine evaluation group. | the th1/th2 profile that follows human vaccination may profoundly influence the subsequent course of disease after infection. however, the ability to detect il-4 has been limited outside trials of live vaccination. by using methods in which memory effector cells are allowed to antigenically expand by short term culture, followed by low-dose mitogenic stimulation, we have been able to follow the th1/th2 profile in hiv-1 volunteers enrolled in two phase i studies of hiv immunogens (a recombinant g ... | 1998 | 9486388 |
| identification of a peptide inducing experimental autoimmune uveoretinitis (eau) in h-2ak-carrying mice. | when certain strains of mice bearing h-2ak are immunized with the interphotoreceptor retinoid-binding protein (irbp), eau is induced. thus far uveitogenic determinant(s) has not been determined in the h-2ak mouse system. in addition it is hard to prepare purified irbp. in the present study, to circumvent these problems we attempted to identify uveitogenic peptides derived from bovine irbp in h-2ak haplotype mice. six peptides which had been selected according to the h-2ak binding motif (dxxxxxxx ... | 1998 | 9486417 |
| structural properties of lipopolysaccharides from rickettsia typhi and rickettsia prowazekii and their chemical similarity to the lipopolysaccharide from proteus vulgaris ox19 used in the weil-felix test. | the lipopolysaccharides (lpss) isolated from typhus group (tg) rickettsiae rickettsia typhi and rickettsia prowazekii were characterized by chemical analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) followed by silver staining. lpss from two species of tg rickettsiae contained glucose, 3-deoxy-d-manno-octulosonic acid, glucosamine, quinovosamine, phosphate, and fatty acids (beta-hydroxylmyristic acid and heneicosanoic acid) but not heptose. the o-polysaccharides o ... | 1998 | 9488376 |
| identification of linked legionella pneumophila genes essential for intracellular growth and evasion of the endocytic pathway. | legionella pneumophila replicates within a specialized phagosome in cultured cells, a function necessary for its pathogenicity. the replicative phagosome lacks membrane marker proteins, such as the glycoprotein lamp-1, that are indicators of the normal endocytic pathway. we describe the isolation of several legionella genes essential for intracellular growth and evasion of the endocytic pathway, using a genetic and cell biological approach. we screened 4,960 ethyl methanesulfonate-mutagenized co ... | 1998 | 9488381 |
| characterization of a chlamydia psittaci dna binding protein (euo) synthesized during the early and middle phases of the developmental cycle. | the euo gene (for early upstream open reading frame) of chlamydia psittaci was previously found to be transcribed better at 1 than at 24 h postinfection. we found that the euo gene encodes a minor protein that is expressed within 1 h of infection of host cells with c. psittaci 6bc but that protein quantity peaks during the logarithmic growth phase of reticulate bodies (rbs), declines late in the infection (after 20 h) when rbs reorganize into elementary bodies (ebs), and is absent in infectious ... | 1998 | 9488410 |
| effect of heat inactivation of serum on bordetella pertussis antibody determination by enzyme-linked immunosorbent assay. | the effect of heat inactivation on bordetella pertussis antibodies determined by enzyme-linked immunosorbent assay (elisa) was studied. sera were heated at increasing temperatures (from 30 to 50 degrees c at 5 degrees c increments and from 52 to 70 degrees c at 2 degrees c increments). between 30 and 50 degrees c, no significant differences were observed in immunoglobin g (igg) antibodies to pertussis toxin (pt). from 50 to 56 degrees c the antibody values were twofold higher than those of unina ... | 1998 | 9488826 |
| on the role of endogenous g-protein beta gamma subunits in n-type ca2+ current inhibition by neurotransmitters in rat sympathetic neurones. | 1. using whole-cell and perforated-patch recordings, we have examined the part played by endogenous g-protein beta gamma subunits in neurotransmitter-mediated inhibition of n-type ca2+ channel current (ica) in dissociated rat superior cervical sympathetic neurones. 2. expression of the c-terminus domain of beta-adrenergic receptor kinase 1 (beta ark1), which contains the consensus motif (qxxer) for binding g beta gamma, reduced the fast (pertussis toxin (ptx)-sensitive) and voltage-dependent inh ... | 1998 | 9490860 |
| construction and characterisation of salmonella typhimurium aroa simultaneously expressing the five pertussis toxin subunits. | pertussis toxin (pt) is a major protective antigen of bordetella pertussis, the causative agent of whooping cough. current vaccines against whooping cough are administered parenterally, and generate a systemic immune response. an alternative to this approach is to stimulate mucosal and systemic immune responses by oral immunisation with live vaccine strains of salmonella spp. we have individually expressed the five pt subunits in salmonella typhimurium aroa and subsequently expressed a synthetic ... | 1998 | 9491507 |
| [pertussis: current aspects of diagnosis, therapy and prevention]. | pertussis (whooping cough) may occur at any age. beside the typical course of the disease in three stages, atypical courses are observed not infrequently, particularly in adults. in early pertussis, isolation of bordetella pertussis from nasopharyngeal secretions is the diagnostic method of choice. the polymerase chain reaction is a promising, albeit still investigational diagnostic method. in longstanding cough, serology is the method of choice. pertussis is treated with erythromycin in high do ... | 1998 | 9492614 |
| [a mobile genetic element on a bordetella pertussis chromosome stimulates cointegrate formation in escherichia coli strains]. | this work continues a series of reports devoted to the study of a repeated sequence isolated from the bordetella pertussis chromosome (rsbp--repeated sequence of bordetella pertussis). the rsbp was earlier demonstrated to have a structure similar to is elements and exhibit some properties of mobile genetic elements. the results of this work demonstrate the ability of this novel genetic element to stimulate the formation of cointegrates between independent replicons. we have studied the structure ... | 1997 | 9493020 |
| bacterial locomotion and signal transduction. | 1998 | 9495737 | |
| computational learning reveals coiled coil-like motifs in histidine kinase linker domains. | the recent rapid growth of protein sequence databases is outpacing the capacity of researchers to biochemically and structurally characterize new proteins. accordingly, new methods for recognition of motifs and homologies in protein primary sequences may be useful in determining how these proteins might function. we have applied such a method, an iterative learning algorithm, to analyze possible coiled coil domains in histidine kinase receptors. the potential coiled coils have not yet been struc ... | 1998 | 9501159 |
| bacterial community dynamics during start-up of a trickle-bed bioreactor degrading aromatic compounds. | this study was performed with a laboratory-scale fixed-bed bioreactor degrading a mixture of aromatic compounds (solvesso100). the starter culture for the bioreactor was prepared in a fermentor with a wastewater sample of a care painting facility as the inoculum and solvesso100 as the sole carbon source. the bacterial community dynamics in the fermentor and the bioreactor were examined by a conventional isolation procedure and in situ hybridization with fluorescently labeled rrna-targeted oligon ... | 1998 | 9501433 |
| prevalence of markers of exposure to bordetella pertussis among italian young adults. | titers of serum antibody and cell-mediated immunity (cmi) to bordetella pertussis antigens were assessed in a cohort of italian military school students for whom the coverage of pertussis vaccination was low. the overall prevalence of igg antibody above the minimum level of detection (mld) was 71.6% for pertussis toxin (pt), 81% for pertactin (prn), and 99% for filamentous hemagglutinin (fha). levels of iga antibody to pt above the mld were detected in 15.9% of the study participants. cmi to fha ... | 1998 | 9502445 |
| species-specific and ubiquitous-dna-based assays for rapid identification of staphylococcus aureus. | staphylococcus aureus is the cause of serious infections in humans, including endocarditis, deep-seated abscesses, and bacteremia, which lead to toxic and septic shock syndromes. rapid and direct identification of this bacterium specifically and ubiquitously directly from clinical specimens would be useful in improving the diagnosis of s. aureus infections in the clinical microbiology laboratory. a wide variety of kits based on biochemical characteristics efficiently identify s. aureus, but the ... | 1998 | 9508283 |
| evaluation of pcr for diagnosis of bordetella pertussis and bordetella parapertussis infections. | pcr, using primers plp1 and plp2, was evaluated for the detection of dna from bordetella pertussis in bacterial strains and in nasopharyngeal samples from patients with a cough lasting at least 7 days. the assay could detect dna from 6 cfu of b. pertussis/10 microl of sample. results of the pcr assay were compared with those of cultures, a determination of serum antibodies against pertussis toxin and filamentous hemagglutinin, and a clinical evaluation of 2,442 coughing episodes. the overall sen ... | 1998 | 9508295 |
| iron, a novel outer membrane siderophore receptor characteristic of salmonella enterica. | speciation in enterobacteria involved horizontal gene transfer. therefore, analysis of genes acquired by horizontal transfer that are present in one species but not its close relatives is expected to give insights into how new bacterial species were formed. in this study we characterize iron, a gene located downstream of the irobc operon in the iroa locus of salmonella enterica serotype typhi. like irobc, the iron gene is present in all phylogenetic lineages of s. enterica but is absent from clo ... | 1998 | 9515912 |
| hybrid bordetella pertussis-escherichia coli rna polymerases: selectivity of promoter activation. | we constructed hybrid bordetella pertussis-escherichia coli rna polymerases and compared productive interactions between transcription activators and cognate rna polymerase subunits in an in vitro transcription system. virulence-associated genes of b. pertussis, in the presence of their activator bvga, are transcribed by all variants of hybrid rna polymerases, whereas transcription at the e. coli lac promoter regulated by the cyclic amp-catabolite gene activator protein has an absolute requireme ... | 1998 | 9515928 |
| in vitro and in vivo antibacterial activities of cs-834, a new oral carbapenem. | cs-834 is a prodrug of the carbapenem r-95867, developed by sankyo co., ltd., tokyo, japan. to investigate the possibility that cs-834 may be the first carbapenem usable in an oral dosage form, its in vitro antibacterial activity (as r-95867) and in vivo antibacterial activity were compared with those of cefpodoxime proxetil, cefditoren pivoxil, cefdinir, ofloxacin, imipenem, and amoxicillin. r-95867 had high levels of activity against methicillin-susceptible staphylococci and streptococci, incl ... | 1998 | 9517932 |
| evaluation of an immunoglobulin g enzyme-linked immunosorbent assay for pertussis toxin and filamentous hemagglutinin in diagnosis of pertussis in senegal. | the enzyme-linked immunosorbent assay is widely employed for the serological diagnosis of pertussis. it is generally concluded that a significant increase in specific immunoglobulin g (igg) or iga against the pertussis toxin (pt) or against filamentous hemagglutinin (fha) in paired sera correlates with bordetella pertussis infection. however, this type of diagnosis of pertussis has mainly been applied to unvaccinated children, with timely sampling of acute- and convalescent-phase sera. in curren ... | 1998 | 9521133 |
| immunoreactivity of five monoclonal antibodies against the 37-kilodalton common cell wall protein (psaa) of streptococcus pneumoniae. | five monoclonal antibodies (mabs) were produced against the streptococcus pneumoniae pneumococcal surface adhesin a (psaa) 37-kda common cell wall protein. these antibodies were used in a dot immunoblot and western blot study of clinical isolates of s. pneumoniae to detect the presence of the protein. by both assays, the mabs reacted with clinical isolates representing the 23 type-specific serotypes present in the licensed pneumococcal polysaccharide vaccine. western blot analysis confirmed the ... | 1998 | 9521144 |
| allelic retrieval: a scheme to facilitate the repeated isolation of a specific segment of the bordetella pertussis chromosome. | a plasmid vector was designed, constructed, and used for the repeated retrieval of the bvga gene from a number of bordetella pertussis strains that, due to mutations in this gene, exhibited interesting phenotypes regarding the regulation of virulence genes. the vector was used in a scheme called allelic retrieval that exploits two cross-overs between cloned plasmid and native chromosomal sequences flanking the bvga gene. this scheme is very similar to allelic exchange through the use of plasmid ... | 1998 | 9524261 |
| evaluation of a "lexically assign, logically refine" strategy for semi-automated integration of overlapping terminologies. | to evaluate a "lexically assign, logically refine" (lalr) strategy for merging overlapping healthcare terminologies. this strategy combines description logic classification with lexical techniques that propose initial term definitions. the lexically suggested initial definitions are manually refined by domain experts to yield description logic definitions for each term in the overlapping terminologies of interest. logic-based techniques are then used to merge defined terms. | 1998 | 9524353 |
| changes in immunological and neuronal conditions markedly altered antibody response to intracerebroventricularly injected ovalbumin in the rat. | the serum antibody response to ovalbumin (oa) has been investigated following intracerebroventricular (i.c.v.) and intravenous administration of antigen in the rat, under altered neuronal and immunological conditions. i.c.v. administration of antigen was far more potent in eliciting humoral immune response. central nervous system (cns) immunization under the conditions of disrupted blood-brain barrier decreased anti-oa antibody production. peripheral polyclonal stimulation with bordetella pertus ... | 1997 | 9524962 |
| intranasal administration of a meningococcal outer membrane vesicle vaccine induces persistent local mucosal antibodies and serum antibodies with strong bactericidal activity in humans. | a nasal vaccine, consisting of outer membrane vesicles (omvs) from group b neisseria meningitidis, was given to 12 volunteers in the form of nose drops or nasal spray four times at weekly intervals, with a fifth dose 5 months later. each nasal dose consisted of 250 microg of protein, equivalent to 10 times the intramuscular dose that was administered twice with a 6-week interval to 11 other volunteers. all individuals given the nasal vaccine developed immunoglobulin a (iga) antibody responses to ... | 1998 | 9529050 |
| pseudomonas aeruginosa invasion and cytotoxicity are independent events, both of which involve protein tyrosine kinase activity. | pseudomonas aeruginosa clinical isolates exhibit invasive or cytotoxic phenotypes. cytotoxic strains acquire some of the characteristics of invasive strains when a regulatory gene, exsa, that controls the expression of several extracellular proteins, is inactivated. exsa mutants are not cytotoxic and can be detected within epithelial cells by gentamicin survival assays. the purpose of this study was to determine whether epithelial cell invasion precedes and/or is essential for cytotoxicity. this ... | 1998 | 9529067 |
| a recombinant live attenuated strain of vibrio cholerae induces immunity against tetanus toxin and bordetella pertussis tracheal colonization factor. | an attenuated strain of vibrio cholerae was used as a carrier for the expression of heterologous antigens such as fragment c from tetanus toxin (tetc) and tracheal colonization factor from bordetella pertussis (tcf). in vitro, high levels of protein were obtained when the escherichia coli nirb promoter was used and the bacteria were grown with low aeration. intranasal immunization of mice with iem101 expressing tetc elicited serum vibriocidal activity and induced antibodies against tetanus toxin ... | 1998 | 9529093 |
| role of adenylate cyclase-hemolysin in alveolar macrophage apoptosis during bordetella pertussis infection in vivo. | bordetella pertussis induces in vitro apoptosis of murine alveolar macrophages by a mechanism that is dependent on expression of bacterial adenylate cyclase-hemolysin. using a murine respiratory model, we found in this study that intranasal infection with a parental b. pertussis strain, but not with an isogenic variant deficient in the expression of all toxins and adhesins, induced a marked neutrophil accumulation in the bronchoalveolar lavage fluid and an early decrease in macrophage numbers. t ... | 1998 | 9529102 |
| bordetella pertussis filamentous hemagglutinin enhances the immunogenicity of liposome-delivered antigen administered intranasally. | in an attempt to increase the immunogenicity of mucosally delivered antigens, we incorporated the bordetella pertussis filamentous hemagglutinin (fha) adhesin into liposomes containing the glutathione s-transferase of schistosoma mansoni (sm28gst) as a model antigen. outbred mice immunized twice intranasally with liposomes containing a constant suboptimal dose of sm28gst and increasing doses of fha produced anti-sm28gst antibodies in a fha dose-dependent manner. the addition of 3 microg of fha t ... | 1998 | 9529111 |
| pertussis toxin-sensitive gtp-binding proteins characterized in synaptosomal fractions of embryonic avian cerebral cortex. | pertussis toxin (ptx)-sensitive gtp-binding proteins (g proteins) are essential intermediaries subserving neuronal signal transduction pathways that regulate excitation-secretion coupling. despite this established role, relatively little is known regarding the identity, subcellular distribution, and relative abundance of this class of g proteins in synaptic nerve endings. here, sucrose density gradient centrifugation was combined with 1- and 2-dimensional gel electrophoresis to characterize ptx- ... | 1998 | 9530821 |
| diphtheria, tetanus and whole cell pertussis vaccine combined with hepatitis b vaccines: a comparison of two doses (10 microg and 5 microg). | a combined diphtheria-tetanus-whole cell pertussis-hepatitis b (dtpwhb) vaccine might facilitate the achievement of universal vaccination of infants against hepatitis b. | 1998 | 9535247 |
| distinct t-cell subtypes induced with whole cell and acellular pertussis vaccines in children. | recent clinical trials have demonstrated that new generation acellular pertussis vaccines can confer protection against whooping cough. however, the mechanism of protective immunity against bordetella pertussis infection induced by vaccination remains to be defined. we have examined cellular immune responses in children immunized with a range of acellular and whole cell pertussis vaccines. immunization of children with a potent whole-cell vaccine induced b. pertussis-specific t cells that secret ... | 1998 | 9536112 |
| characterization of the bvgr locus of bordetella pertussis. | bordetella pertussis, the causative agent of whooping cough, produces a wide array of factors that are associated with its ability to cause disease. the expression and regulation of these virulence factors is dependent upon the bvg locus (originally designated the vir locus), which encodes two proteins: bvga, a 23-kda cytoplasmic protein, and bvgs, a 135-kda transmembrane protein. it is proposed that bvgs responds to environmental signals and interacts with bvga, a transcriptional regulator whic ... | 1998 | 9537363 |
| identification of a new dna region specific for members of mycobacterium tuberculosis complex. | the successful use of dna amplification for the detection of tuberculous mycobacteria crucially depends on the choice of the target sequence, which ideally should be present in all tuberculous mycobacteria and absent from all other bacteria. in the present study we developed a pcr procedure based on the intergenic region (ir) separating two genes encoding a recently identified mycobacterial two-component system named senx3-regx3. the senx3-regx3 ir is composed of a novel type of repetitive seque ... | 1998 | 9542912 |
| diversity of helicobacter pylori vaca and caga genes and relationship to vaca and caga protein expression, cytotoxin production, and associated diseases. | the vacuolating cytotoxin and the cytotoxin-associated protein, encoded by vaca and caga, respectively, are important virulence determinants of helicobacter pylori. sixty-five h. pylori strains were isolated from dyspeptic patients (19 with peptic ulcer disease, 43 with chronic gastritis, and 3 with gastric cancer) and studied for differences in the vaca and caga genes and their relationship to vaca and caga expression, cytotoxin activity, and the clinical outcome of infection. by pcr, fifty-fou ... | 1998 | 9542913 |
| bordetella parapertussis infection in children: epidemiology, clinical symptoms, and molecular characteristics of isolates. | the clinical trial conducted in italy to evaluate the efficacy of acellular pertussis vaccines provided an opportunity to estimate the frequency of clinical infections with bordetella parapertussis and to compare the clinical characteristics of children suffering from bordetella pertussis illness with those of children with b. parapertussis illness. this study dealt with 76 b. parapertussis infections diagnosed from a population of 15,601 children participating in the follow-up of suspected case ... | 1998 | 9542925 |
| induction of abnormal respiratory sounds by capsaicin in rats previously infected with bordetella pertussis. | sprague dawley rats, previously infected with phase-i bordetella pertussis, developed more severe abnormal respiratory sounds than normal animals, but not coughing, when exposed to aerosolized capsaicin, one of several cough-inducing agents tested. stethoscope examination suggested that greater production of pulmonary mucus might be occurring after capsaicin challenge of the infected animals, compared to the uninfected controls. rats of three other strains gave characteristically different respo ... | 1998 | 9544781 |
| t helper 1 (th1) and th2 characteristics start to develop during t cell priming and are associated with an immediate ability to induce immunoglobulin class switching. | the respective production of specific immunoglobulin (ig)g2a or igg1 within 5 d of primary immunization with swiss type mouse mammary tumor virus [mmtv(sw)] or haptenated protein provides a model for the development of t helper 1 (th1) and th2 responses. the antibody-producing cells arise from cognate t cell b cell interaction, revealed by the respective induction of cgamma2a and cgamma1 switch transcript production, on the third day after immunization. t cell proliferation and upregulation of m ... | 1998 | 9547331 |
| age-related loss of calcitriol stimulation of phosphoinositide hydrolysis in rat skeletal muscle. | we have examined the effects in vitro of calcitriol [1,25(oh)2d3], the hormonal form of vitamin d3, on the breakdown of membrane phosphoinositides in skeletal muscle from young (3 months) and aged (24 months) rats. calcitriol (10(-9) m) induced a rapid and transient release of ip3/inositol phosphates and diacylglycerol (dag) from muscle slices/membranes prelabeled with [3h]myo-inositol and [3h]arachidonate, respectively. inositol phosphate release was maximal at 15 s and then declined. the effec ... | 1998 | 9548216 |
| quantitative systematic review of randomised controlled trials comparing antibiotic with placebo for acute cough in adults. | to assess whether antibiotic treatment for acute cough is effective and to measure the side effects of such treatment. | 1998 | 9552842 |
| enterocins l50a and l50b, two novel bacteriocins from enterococcus faecium l50, are related to staphylococcal hemolysins. | enterocin l50 (entl50), initially referred to as pediocin l50 (l. m. cintas, j. m. rodríguez, m. f. fernández, k. sletten, i. f. nes, p. e. hernández, and h. holo, appl. environ. microbiol. 61:2643-2648, 1995), is a plasmid-encoded broad-spectrum bacteriocin produced by enterococcus faecium l50. it has previously been purified from the culture supernatant and partly sequenced by edman degradation. in the present work, the nucleotide sequence of the entl50 locus was determined, and several putati ... | 1998 | 9555877 |
| the periplasmic, group iii catalase of vibrio fischeri is required for normal symbiotic competence and is induced both by oxidative stress and by approach to stationary phase. | the catalase gene, kata, of the sepiolid squid symbiont vibrio fischeri has been cloned and sequenced. the predicted amino acid sequence of kata has a high degree of similarity to the recently defined group iii catalases, including those found in haemophilus influenzae, bacteroides fragilis, and proteus mirabilis. upstream of the predicted start codon of kata is a sequence that closely matches the consensus sequence for promoters regulated in escherichia coli by the alternative sigma factor enco ... | 1998 | 9555890 |
| effect of dirithromycin on haemophilus influenzae infection of the respiratory mucosa. | macrolides have properties other than their antibiotic action which may benefit patients with airway infections. we have investigated the effect of dirithromycin (0.125 to 8.0 microg/ml) on the interaction of haemophilus influenzae with respiratory mucosa in vitro using human nasal epithelium, adenoid tissue, and bovine trachea. dirithromycin did not affect the ciliary beat frequency of the nasal epithelium or the transport of mucus on bovine trachea, but dirithromycin (1 microg/ml) did reduce t ... | 1998 | 9559781 |
| in vitro susceptibilities of bordetella pertussis and bordetella parapertussis to two ketolides (hmr 3004 and hmr 3647), four macrolides (azithromycin, clarithromycin, erythromycin a, and roxithromycin), and two ansamycins (rifampin and rifapentine). | when tested by agar dilution on mueller-hinton agar supplemented with 5% horse blood, the ketolides hmr 3004 and hmr 3647 were slightly more active (mic at which 90% of the isolates were inhibited [mic90], 0.03 microg/ml) against bordetella pertussis than azithromycin, clarithromycin, erythromycin a, and roxithromycin. azithromycin (mic90, 0.06 microg/ml) was the most active compound against b. parapertussis. rifampin and rifapentine were considerably less active. | 1998 | 9559823 |
| a tellurite-resistance genetic determinant from phytopathogenic pseudomonads encodes a thiopurine methyltransferase: evidence of a widely-conserved family of methyltransferases. | a tellurite-resistance genetic determinant was isolated from the pea blight pathogen pseudomonas syringae pathovar pisi by a shotgun strategy involving a tellurite-selective screening in escherichia coli. a 1.65 kb tellurite resistance insert was obtained and analysed. it harbours a single complete and functional orf encoding a deduced protein of 24, 445 da. the deduced aa sequence shows significant similarities with the complete human thiopurine methyltransferase enzyme, a methyltransferase fro ... | 1998 | 9565678 |
| molecular characterization of the aeromonas hydrophila aroa gene and potential use of an auxotrophic aroa mutant as a live attenuated vaccine. | the aroa gene of aeromonas hydrophila so2/2, encoding 5-enolpyruvylshikimate 3-phosphate synthase, was cloned by complementation of the aroa mutation in escherichia coli k-12 strain ab2829, and the nucleotide sequence was determined. the nucleotide sequence of the a. hydrophila aroa gene encoded a protein of 440 amino acids which showed a high degree of homology to other bacterial aroa proteins. to obtain an effective attenuated live vaccine against a. hydrophila infections in fish, the aroa gen ... | 1998 | 9573055 |
| nasopharyngeal colonization with nontypeable haemophilus influenzae in chinchillas. | colonization of the nasopharynx by a middle ear pathogen is the first step in the development of otitis media in humans. the establishment of an animal model of nasopharyngeal colonization would therefore be of great utility in assessing the potential protective ability of candidate vaccine antigens (especially adhesins) against otitis media. a chinchilla nasopharyngeal colonization model for nontypeable haemophilus influenzae (nthi) was developed with antibiotic-resistant strains. this model do ... | 1998 | 9573078 |
| burkholderia cepacia produces a hemolysin that is capable of inducing apoptosis and degranulation of mammalian phagocytes. | burkholderia cepacia is an opportunistic pathogen that has become a major threat to individuals with cystic fibrosis (cf). in approximately 20% of patients, pulmonary colonization with b. cepacia leads to cepacia syndrome, a fatal fulminating pneumonia sometimes associated with septicemia. it has been reported that culture filtrates of clinically derived strains of b. cepacia are hemolytic. in this study, we have characterized a factor which contributes to this hemolytic activity and is secreted ... | 1998 | 9573086 |
| identification and characterization of heparin binding regions of the fim2 subunit of bordetella pertussis. | bordetella pertussis fimbriae bind to sulfated sugars such as heparin through the major subunit fim2. the fim2 subunit contains two regions, designated h1 and h2, which show sequence similarity with heparin binding regions of fibronectin, and the role of these regions in heparin binding was investigated with maltose binding protein (mbp)-fim2 fusion proteins. deletion derivatives of mbp-fim2 showed that both regions are important for binding to heparin. the role of h2 in heparin binding was conf ... | 1998 | 9573115 |
| nucleotide sequence and spatiotemporal expression of the vibrio cholerae viesab genes during infection. | the ivivii gene of vibrio cholerae was previously identified by a screen for genes induced during intestinal infection. in the present study, nucleotide sequence analysis revealed that ivivii is a 1,659-bp open reading frame, herein designated vieb, that is predicted to be last in a tricistronic operon (viesab). the deduced amino acid sequence of vies exhibited similarity to the sensor kinase component, and those of viea and vieb were similar to the response regulator components, respectively, o ... | 1998 | 9573178 |
| mutations affecting the alpha subunit of bordetella pertussis rna polymerase suppress growth inhibition conferred by short c-terminal deletions of the response regulator bvga. | the effects of short deletions of the c terminus of the bvga response regulator protein of the bvgas two-component system were examined in bordetella pertussis. when present as a single copy in the chromosome, deletions removing as few as two amino acids conferred a completely bvg- phenotype. when provided in trans, on the broad-host-range plasmid prk290, under the control of the native bvgas promoter, deletions of two or three amino acids conferred a profound growth inhibition which was depende ... | 1998 | 9573202 |
| detection of ureaplasma urealyticum in endotracheal tube aspirates from neonates by pcr. | a pcr-based test was optimized for the detection of ureaplasma urealyticum from neonatal respiratory specimens, with primers directed against the multiple-banded antigen gene (l. j. teng, x. zheng, j. i. glass, h. watson, j. tsai, and g. h. cassell, j. clin. microbiol. 32:1464-1469, 1994). endotracheal tube aspirates (225) from 103 low-birth-weight neonates (<1,250 g) were taken, when possible, at days 0, 4, and 14 after birth and examined by culture and by pcr. of 77 specimens positive by eithe ... | 1998 | 9574683 |
| susceptibility testing of bordetella pertussis. | 1998 | 9574735 | |
| concomitant viral and bordetella pertussis infections in infants. | 1998 | 9576398 | |
| a bacterial two-hybrid system based on a reconstituted signal transduction pathway. | we describe a bacterial two-hybrid system that allows an easy in vivo screening and selection of functional interactions between two proteins. this genetic test is based on the reconstitution, in an escherichia coli cya strain, of a signal transduction pathway that takes advantage of the positive control exerted by camp. two putative interacting proteins are genetically fused to two complementary fragments, t25 and t18, that constitute the catalytic domain of bordetella pertussis adenylate cycla ... | 1998 | 9576956 |
| long-term antibody persistence after booster vaccination with combined tetravalent diphtheria tetanus, whole-cell bordetella pertussis and hepatitis b vaccine in healthy infants. | combining hb vaccine with routine paediatric vaccines has been recognized as the best means of universal vaccination against hepatitis b. our objective was to evaluate the long-term antibody persistence of such a combined vaccine in an area of high hepatitis b endemicity. we have shown that a dtpw-hb vaccine was safe and immunogenic when given as a booster dose at 18 months of age. one month after the booster dose of dtpw-hb vaccine, at least 97.8% of subjects had seroprotective anti-hbsag level ... | 1997 | 9578788 |
| the comparative in-vitro activity of roxithromycin and other antibiotics against bordetella pertussis. | in spite of vaccination programmes, whooping cough epidemics continue to occur. the disease affects all age groups, although its severity is greatest in the young, with infants being particularly vulnerable. erythromycin is generally accepted as the drug of choice both for treatment and for prophylaxis during epidemics. roxithromycin is a macrolide with pharmacokinetic advantages over erythromycin; it is well absorbed, produces high serum concentrations, has a long half-life and penetrates respi ... | 1998 | 9579709 |
| gtpgammas-induced actin polymerisation in vitro: atp- and phosphoinositide-independent signalling via rho-family proteins and a plasma membrane-associated guanine nucleotide exchange factor. | in a cell-free system from neutrophil cytosol gtp(&ggr ;)s can induce an increase in the number of free filament barbed ends and massive actin polymerisation and cross-linking. gtp(&ggr ;)s stimulation was susceptible to an excess of gdp, but not bordetella pertussis toxin and could not be mimicked by aluminium fluoride, myristoylated gtpgammas.gialpha2 or gbeta1gamma2 subunits of trimeric g proteins. in contrast, rhogdi and clostridium difficile toxin b (inactivating rho family proteins) comple ... | 1998 | 9580566 |
| enhanced bradykinin-stimulated phospholipase c activity in murine embryonic stem cells lacking the g-protein alphaq-subunit. | the gene coding for the g-protein alphaq subunit was interrupted by homologous recombination in murine embryonic stem cells (alphaq-null es cells) as detected by southern analysis and reverse-transcriptase pcr. the bradykinin (bk) b2 receptor was stably transfected into wild-type (wt) alphai-2-null and alphaq-null es cells. the b2 receptor bound bk with high affinity and mobilized ca2+. bk also activated phospholipase c (plc), as determined by total inositol phosphate (ip) accumulation in a bord ... | 1997 | 9581559 |
| identification of btr-regulated genes using a titration assay. search for a role for this transcriptional regulator in the growth and virulence of bordetella pertussis. | bordetella pertussis is the causative agent of the respiratory disease pertussis or whopoping cough. btr, an oxygen-responsive transcriptional regulator of b. pertussis, is homologous to the fnr protein of e. coli. using a murine respiratory model, we observed in the present study that btr is important in growth and survival of b. pertussis in vivo. a titration assay was developed that identified genes containing btr binding sites including b. pertussis sodb and btr, e. coli aspa and a new b. pe ... | 1998 | 9583950 |
| homologous and heterologous protection after single intranasal administration of live attenuated recombinant bordetella pertussis. | while single-dose mucosal immunization is best achieved by the use of attenuated live microorganisms, attenuation generally results in decreased immunogenicity. we attenuated bordetella pertussis by the deletion of the pertussis toxin gene. a single intranasal administration of this strain protected against subsequent challenge as well as did the parent strain and better than immunization with commercial vaccine. unexpectedly, this attenuation resulted in increased immunogenicity against the pro ... | 1998 | 9592394 |
| analyses of the cag pathogenicity island of helicobacter pylori. | most strains of helicobacter pylori from patients with peptic ulcer disease or intestinal-type gastric cancer carry caga, a gene that encodes an immunodominant protein of unknown function, whereas many of the strains from asymptomatically infected persons lack this gene. recent studies showed that the caga gene lies near the right end of a approximately 37kb dna segment (a pathogenicity island, or pai) that is unique to caga+ strains and that the cag pai was split in half by a transposable eleme ... | 1998 | 9593295 |
| bacterial perturbation of cytokine networks. | 1998 | 9596695 | |
| cytochalasin-induced actin disruption of polarized enterocytes can augment internalization of bacteria. | cytochalasin-induced actin disruption has often been associated with decreased bacterial internalization by cultured epithelial cells, although polarized enterocytes have not been systematically studied. in assays using confluent polarized ht-29 enterocytes, cytochalasin d appeared to increase internalization of wild-type salmonella typhimurium, proteus mirabilis, and escherichia coli. hela and hep-2 epithelial cells, as well as ht-29 and caco-2 enterocytes, were used to clarify this unexpected ... | 1998 | 9596696 |
| molecular characterization of mycoplasma arthritidis variable surface protein maa2. | earlier studies implied a role for mycoplasma arthritidis surface protein maa2 in cytadherence and virulence and showed that it exhibited both size and phase variability. here we report the further analysis of maa2 and the cloning and sequencing of the maa2 gene from two m. arthritidis strains, 158p10p9 and h606, expressing two size variants of maa2. triton x-114 partitioning and metabolic labeling with [3h]palmitic acid suggested lipid modification of maa2. surface exposure of the c terminus wa ... | 1998 | 9596719 |
| clostridium difficile toxin b induces apoptosis in intestinal cultured cells. | toxigenic strains of the anaerobic bacterium clostridium difficile produce at least two large, single-chain protein exotoxins involved in the pathogenesis of antibiotic-associated diarrhea and colitis. toxin a (cda) is a cytotoxic enterotoxin, while toxin b (cdb) is a more potent cytotoxin lacking enterotoxic activity. this study dealt with cdb, providing the first evidence that intestinal cells exposed to this toxin exhibit typical features of apoptosis in that a significant proportion of the t ... | 1998 | 9596731 |
| neither the bvg- phase nor the vrg6 locus of bordetella pertussis is required for respiratory infection in mice. | in bordetella species, the bvgas sensory transduction system mediates an alteration between the bvg+ phase, characterized by expression of adhesins and toxins, and the bvg- phase, characterized by the expression of motility and coregulated phenotypes in bordetella bronchiseptica and by the expression of vrg loci in bordetella pertussis. since there is no known environmental or animal reservoir for b. pertussis, the causative agent of whooping cough, it has been assumed that this phenotypic alter ... | 1998 | 9596745 |
| elution of lipopolysaccharides from polyacrylamide gels. | a simple procedure for elution in water of bacterial lipopolysaccharides (lps) from sodium dodecyl sulfate-polyacrylamide gels is described. it consists of the combination of three principal steps: first, highly sensitive on-gel lps detection (1-10 ng/band) with zinc-imidazole (negative or reverse staining); second, washing of the individual lps band in a solution of a zinc-complexing agent (e.g., 100 mm edta); and finally, elution of the lps (100-200 microliters water for a 0.5-microgram lps ba ... | 1998 | 9606157 |
| nitric oxide induction in murine macrophages and spleen cells by whole-cell bordetella pertussis vaccine. | nitric oxide (no) induction was studied in the peritoneal macrophages and spleen cells of female nih mice immunised with whole cell bordetella pertussis vaccines of moderate and high potency, respectively. compared with controls receiving diluent only, the macrophages and spleen cells of the vaccinated mice developed high levels of reactive nitrogen intermediates from the third day after injection. the nitrite concentrations achieved maximum values at the 10th day, but significant levels persist ... | 1998 | 9607004 |
| the efficacy of a whole cell pertussis vaccine and fimbriae against bordetella pertussis and bordetella parapertussis infections in a respiratory mouse model. | due to local and systemic side-effects, the currently used, highly effective, whole-cell pertussis vaccines (wcvs) will be replaced by acellular vaccines (acvs) in some countries. these acvs contain detoxified pertussis toxin, either alone or in combination with the filamentous haemagglutinin, pertactin and fimbriae. ongoing clinical trials show that acvs are clearly less reactogenic than wcvs and that acvs comprised of three to five proteins are highly efficacious in inducing protection against ... | 1998 | 9607064 |
| epidemiology of pertussis in french hospitals in 1993 and 1994: thirty years after a routine use of vaccination. | despite widespread vaccination during 30 years, the hypothesis of a resurgence of pertussis in france has been raised by outbreaks and sporadic case reports. no surveillance data were available after 1985. | 1998 | 9613656 |
| short-sequence dna repeats in prokaryotic genomes. | short-sequence dna repeat (ssr) loci can be identified in all eukaryotic and many prokaryotic genomes. these loci harbor short or long stretches of repeated nucleotide sequence motifs. dna sequence motifs in a single locus can be identical and/or heterogeneous. ssrs are encountered in many different branches of the prokaryote kingdom. they are found in genes encoding products as diverse as microbial surface components recognizing adhesive matrix molecules and specific bacterial virulence factors ... | 1998 | 9618442 |
| nontypeable haemophilus influenzae: pathogenesis and prevention. | in this paper, we describe the ability of nontypeable haemophilus influenzae (nthi) to coexist with the human host and the devastating results associated with disruption of the delicate state of balanced pathogenesis, resulting in both acute and chronic respiratory tract infections. it has been seen that the strains of nthi causing disease show a marked genetic and phenotypic diversity but that changes in the lipooligosaccharide (los) and protein size and antigenicity in chronically infected ind ... | 1998 | 9618443 |
| acylation of escherichia coli hemolysin: a unique protein lipidation mechanism underlying toxin function. | the pore-forming hemolysin (hlya) of escherichia coli represents a unique class of bacterial toxins that require a posttranslational modification for activity. the inactive protoxin pro-hlya is activated intracellularly by amide linkage of fatty acids to two internal lysine residues 126 amino acids apart, directed by the cosynthesized hlyc protein with acyl carrier protein as the fatty acid donor. this action distinguishes hlyc from all bacterial acyltransferases such as the lipid a, lux-specifi ... | 1998 | 9618444 |
| type iii protein secretion systems in bacterial pathogens of animals and plants. | various gram-negative animal and plant pathogens use a novel, sec-independent protein secretion system as a basic virulence mechanism. it is becoming increasingly clear that these so-called type iii secretion systems inject (translocate) proteins into the cytosol of eukaryotic cells, where the translocated proteins facilitate bacterial pathogenesis by specifically interfering with host cell signal transduction and other cellular processes. accordingly, some type iii secretion systems are activat ... | 1998 | 9618447 |
| the ti plasmid increases the efficiency of agrobacterium tumefaciens as a recipient in virb-mediated conjugal transfer of an incq plasmid. | the t-dna transfer apparatus of agrobacterium tumefaciens mediates the delivery of the t-dna into plant cells, the transfer of the incq plasmid rsf1010 into plant cells, and the conjugal transfer of rsf1010 between agrobacteria. we show in this report that the agrobacterium-to-agrobacterium conjugal transfer efficiencies of rsf1010 increase dramatically if the recipient strain, as well as the donor strain, carries a wild-type ti plasmid and is capable of vir gene expression. investigation of pos ... | 1998 | 9618538 |
| transfer of allergic airway responses with serum and lymphocytes from rats sensitized to dust mite. | house dust mite (hdm) antigen is one of the most common allergens associated with extrinsic asthma. in a model of allergic lung disease, brown norway (bn) rats sensitized to hdm with alum and bordetella pertussis adjuvants produce high levels of ige antibody and experience bronchoconstriction, increased airway hyperresponsiveness (ahr) to acetylcholine (ach), and pulmonary inflammation after antigen challenge. the purpose of this study was to determine whether these asthmatic symptoms could be t ... | 1998 | 9620937 |
| transcriptional regulation of alcaligenes eutrophus hydrogenase genes. | alcaligenes eutrophus h16 produces a soluble hydrogenase (sh) and a membrane-bound hydrogenase (mbh) which catalyze the oxidation of h2, supplying the organism with energy for autotrophic growth. the promoters of the structural genes for the sh and the mbh, psh and pmbh, respectively, were identified by means of the primer extension technique. both promoters were active in vivo under hydrogenase-derepressing conditions but directed only low levels of transcription under condition which repressed ... | 1998 | 9620971 |
| protective immunity induced by oral immunization with a rotavirus dna vaccine encapsulated in microparticles. | dna vaccines are usually given by intramuscular injection or by gene gun delivery of dna-coated particles into the epidermis. induction of mucosal immunity by targeting dna vaccines to mucosal surfaces may offer advantages, and an oral vaccine could be effective for controlling infections of the gut mucosa. in a murine model, we obtained protective immune responses after oral immunization with a rotavirus vp6 dna vaccine encapsulated in poly(lactide-coglycolide) (plg) microparticles. one dose of ... | 1998 | 9621034 |
| serum resistance in bvg-regulated mutants of bordetella pertussis. | serum resistance, or resistance to killing by antibody dependent pathway of complement, in bordetella pertussis is bvg-regulated and the bordetella resistance to killing (brk) locus mediates much of the resistance. here we examined whether other bvg-regulated proteins contribute to serum resistance. we found that neither pertussis toxin, adenylate cyclase toxin, filamentous hemagglutinin, dermonecrotic toxin, tracheal colonization factor, nor vag8 mutants were sensitive to serum killing compared ... | 1998 | 9631546 |
| oral vaccination against tetanus: comparison of the immunogenicities of salmonella strains expressing fragment c from the nirb and htra promoters. | we have found the in vivo-regulated nirb promoter (pnirb) to be effective for directing expression of a number of antigens in salmonella in vivo. we wished to determine if other in vivo-regulated promoters have utility for antigen expression in salmonella and to compare the effectiveness of these promoters with that of pnirb. to this end, we have devised a scheme that allows the promoter element of the pnirb-fragment c plasmid ptetnir15 to be swapped with other promoters of interest. we demonstr ... | 1998 | 9632569 |
| heterogeneity in levels of vacuolating cytotoxin gene (vaca) transcription among helicobacter pylori strains. | broth culture supernatants from tox+ helicobacter pylori strains induce vacuolation of hela cells in vitro and contain vaca in concentrations that are higher than those found in supernatants from tox- h. pylori strains. to investigate the basis for this phenomenon, we analyzed the transcription of the vacuolating cytotoxin gene (vaca) in eight tox+ strains (each with a type s1/m1 vaca genotype) and nine tox- strains (each with a type s2/m2 vaca genotype). most of the tox+ and tox- strains tested ... | 1998 | 9632570 |
| bioluminescence as a reporter of intracellular survival of bordetella bronchiseptica in murine phagocytes. | the uptake and persistence of bordetella bronchiseptica was characterized in murine phagocytes by using a novel bioluminescence-based reporter system. a mini-tn5 promoter probe carrying the intact lux operon from the terrestrial bacterium photorhabdus luminescens which allowed measurement of light output without the addition of exogenous substrate was constructed. it was used to create a pool of bioluminescent fusion strains of b. bronchiseptica. the internalization and persistence in murine mac ... | 1998 | 9632586 |
| identification and sequence analysis of a 27-kilobase chromosomal fragment containing a salmonella pathogenicity island located at 92 minutes on the chromosome map of salmonella enterica serovar typhimurium lt2. | using a genomic approach, we have identified a new salmonella pathogenicity island, spi-4, which is the fourth salmonella pathogenicity island to be identified. spi-4 was located at 92 min on the chromosome map and was flanked by the ssb and soxsr loci. the dna sequence covering the entire spi-4 and both boundaries was determined. the size of spi-4 was about 25 kb and it contains 18 putative open reading frames (orfs). three of these orfs encode proteins that have significant homology with prote ... | 1998 | 9632606 |
| lipopolysaccharide expression within the genus bordetella: influence of temperature and phase variation. | lpss play an important role in bacterial pathogenesis. in this study, the lps expression of the seven known bordetella species and its dependency on growth temperature was analysed by oxidative silver staining of proteinase-k-treated whole bacteria separated by tricine-sds-page. the bordetellae were found to have extensively variable lps in a species-specific way. in addition, the human and ovine bordetella parapertussis strains exhibited host-specific lps expression. lpss from human b. parapert ... | 1998 | 9639923 |
| aeromonas hydrophila adenylyl cyclase 2: a new class of adenylyl cyclases with thermophilic properties and sequence similarities to proteins from hyperthermophilic archaebacteria. | complementation of an escherichia coli cya mutant with a genomic library from aeromonas hydrophila allowed isolation of clones containing two different cya genes. whereas one of these genes (cyaa) coded for an adenylyl cyclase (ac1) belonging to the previously described class i adenylyl cyclases (acs), the second one (cyab) coded for a protein (ac2) that did not match any previously characterized protein when compared to protein sequence databases. in particular, it did not align with any of mem ... | 1998 | 9642185 |
| pertussis toxin potentiates th1 and th2 responses to co-injected antigen: adjuvant action is associated with enhanced regulatory cytokine production and expression of the co-stimulatory molecules b7-1, b7-2 and cd28. | pertussis toxin (pt) is a major virulence factor of bordetella pertussis which exerts a range of effects on the immune system, including the enhancement of ige, iga and igg production, delayed-type hypersensitivity reactions, and the induction of experimental autoimmune diseases. however, the mechanism by which pt mediates adjuvanticity remains to be defined. in this investigation we have shown that pt can potentiate antigen-specific t cell proliferation and the secretion of ifn-gamma, il-2, il- ... | 1998 | 9645613 |
| evidence for the presence of insulin-dependent diabetes-associated alleles on the distal part of mouse chromosome 6. | type 1 diabetes (iddm) is a complex disorder with multifactorial and polygenic etiology. a genome-wide screen performed in a bc1 cohort of a cross between the nonobese diabetic (nod) mouse with the diabetes-resistant feral strain pwk detected a major locus contributing to diabetes development on the distal part of chromosome 6. unlike the majority of other idd loci identified in intraspecific crosses, susceptibility is associated with the presence of the pwk allele. genetic linkage analysis of c ... | 1998 | 9647636 |
| immunization with a peptide surrogate for double-stranded dna (dsdna) induces autoantibody production and renal immunoglobulin deposition. | anti-double-stranded dna (dsdna) antibodies are the serologic abnormality characteristically associated with systemic lupus erythematosus (sle) and may play an important role in disease pathogenesis. although the anti-dsdna antibodies present in sle are indicative of an antigen-driven response, the antigen has not been conclusively identified. by screening a phage peptide display library, we demonstrated previously that the decapeptide dweysvwlsn is specifically bound by the pathogenic murine ig ... | 1998 | 9653081 |
| phase-variable expression of lipopolysaccharide contributes to the virulence of legionella pneumophila. | with the aid of monoclonal antibody (mab) 2625, raised against the lipopolysaccharide (lps) of legionella pneumophila serogroup 1, subgroup olda, we isolated mutant 811 from the virulent wild-type strain rc1. this mutant was not reactive with mab 2625 and exhibited an unstable phenotype, since we observed an in vitro and in vivo switch of mutant 811 to the mab 2625-positive phenotype, thus restoring the wild-type lps. bactericidal assays revealed that mutant 811 was lysed by serum complement com ... | 1998 | 9653083 |
| interleukin 6 plays a key role in the development of antigen-induced arthritis. | to investigate the direct role of interleukin (il) 6 in the development of rheumatoid arthritis, il-6-deficient (il-6 -/-) mice were backcrossed for eight generations into c57bl/6 mice, a strain of mice with a genetic background of susceptibility for antigen-induced arthritis (aia). both histological and immunological comparisons were made between il-6-deficient (il-6 -/-) mice and wild-type (il-6 +/+) littermates after the induction of aia. although all il-6 +/+ mice developed severe arthritis, ... | 1998 | 9653168 |
| opposing roles of the staphylococcus aureus virulence regulators, agr and sar, in triton x-100- and penicillin-induced autolysis. | the regulation of murein hydrolases is a critical aspect of peptidoglycan growth and metabolism. in the present study, we demonstrate that mutations within the staphylococcus aureus virulence factor regulatory genes, agr and sar, affect autolysis, resulting in decreased and increased autolysis rates, respectively. zymographic analyses of these mutant strains suggest that agr and sar exert their effects on autolysis, in part, by modulating murein hydrolase expression and/or activity. | 1998 | 9658022 |