Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| plasmid-located pathogenicity determinants of serratia entomophila, the causal agent of amber disease of grass grub, show similarity to the insecticidal toxins of photorhabdus luminescens. | serratia entomophila and serratia proteamaculans cause amber disease in the grass grub costelytra zealandica (coleoptera: scarabaeidae), an important pasture pest in new zealand. larval disease symptoms include cessation of feeding, clearance of the gut, amber coloration, and eventual death. a 115-kb plasmid, padap, identified in s. entomophila is required for disease causation and, when introduced into escherichia coli, enables that organism to cause amber disease. a 23-kb fragment of padap tha ... | 2000 | 10960097 |
| dna-based diagnostic approaches for identification of burkholderia cepacia complex, burkholderia vietnamiensis, burkholderia multivorans, burkholderia stabilis, and burkholderia cepacia genomovars i and iii. | bacteria of the burkholderia cepacia complex consist of five discrete genomic species, including genomovars i and iii and three new species: burkholderia multivorans (formerly genomovar ii), burkholderia stabilis (formerly genomovar iv), and burkholderia vietnamiensis (formerly genomovar v). strains of all five genomovars are capable of causing opportunistic human infection, and microbiological identification of these closely related species is difficult. the 16s rrna gene (16s rdna) and reca ge ... | 2000 | 10970351 |
| comprehensive pcr-based assay for detection and species identification of human herpesviruses. | the description and evaluation of a pcr-based assay for the detection and species identification of the eight known human herpesviruses are presented. two primer pairs targeting well-conserved regions of the genome allowed the amplification of the dnas of all known human herpesviruses at a high level of sensitivity (10 to 100 genome copies for most viruses). identification of the virus species was achieved through restriction enzyme digestion with bamhi and bstui, which yielded fragment sizes th ... | 2000 | 10970370 |
| development of a rapid pcr assay specific for staphylococcus saprophyticus and application to direct detection from urine samples. | staphylococcus saprophyticus is one of the most frequently encountered microorganisms associated with acute urinary tract infections (utis) in young, sexually active female outpatients. conventional identification methods based on biochemical characteristics can efficiently identify s. saprophyticus, but the rapidities of these methods need to be improved. rapid and direct identification of this bacterium from urine samples would be useful to improve time required for the diagnosis of s. saproph ... | 2000 | 10970371 |
| anti-caga immunoglobulin g responses correlate with interleukin-8 induction in human gastric mucosal biopsy culture. | helicobacter pylori persists in the human stomach despite eliciting both cellular and humoral immune responses and inducing proinflammatory cytokines. to determine whether local humoral and cytokine responses are related to each other and to histologic responses, we studied 66 japanese patients who underwent gastroscopy. using specific enzyme-linked immunosorbent assays, we examined gastric antral mucosal-organ biopsy culture supernatants to assess interleukin-6 (il-6) and interleukin-8 (il-8) l ... | 2000 | 10973458 |
| escherichia coli alpha-hemolysin (hlya) is heterogeneously acylated in vivo with 14-, 15-, and 17-carbon fatty acids. | alpha-hemolysin (hlya) is a secreted protein virulence factor observed in certain uropathogenic strains of escherichia coli. the active, mature form of hlya is produced by posttranslational modification of the protoxin that is mediated by acyl carrier protein and an acyltransferase, hlyc. we have now shown using mass spectrometry that these modifications, when observed in protein isolated in vivo, consist of acylation at the epsilon-amino groups of two internal lysine residues, at positions 564 ... | 2000 | 10978310 |
| filamentous hemagglutinin and pertussis toxin from bordetella pertussis modulate immune responses to unrelated antigens. | 2000 | 10979938 | |
| laboratory diagnosis of atypical pneumonia. | "atypical pneumonia" is a term loosely applied to lower respiratory tract infections that are not characterized by signs and symptoms of lobar consolidation. this description can apply to disease caused by a variety of bacterial, viral and even protozoan organisms. in reality, differentiation as to etiology of pneumonia cannot be distinguished on the basis of clinical presentation. this review will discuss the epidemiology, clinical manifestations, and laboratory diagnosis of mycoplasma pneumoni ... | 2000 | 10983928 |
| mutagenesis of neisseria meningitidis by in vitro transposition of himar1 mariner. | now that the meningococcal genome sequence has been completed, the lack of a suitable method for saturation mutagenesis remains a major obstacle to the unraveling of the pathogenic propensity of neisseria meningitidis. here, we demonstrate that in vitro himar1 mariner transposition on chromosomal or pcr-amplified meningococcal dna, which is subsequently reintroduced into n. meningitidis by natural transformation, is an extremely efficient mutagenesis method. southern blot analysis, sequencing th ... | 2000 | 10986241 |
| perhaps it is not time to switch from whole cell to acellular pertussis vaccine. | 2000 | 10991602 | |
| in vitro activities of the ketolides telithromycin (hmr 3647) and hmr 3004 compared to those of clarithromycin against slowly growing mycobacteria at phs 6.8 and 7.4. | the in vitro activities of hmr 3647 (telithromycin) and hmr 3004, two novel semisynthetic ketolides, were investigated and compared with that of the reference macrolide drug, clarithromycin, against 34 strains of slowly growing mycobacteria at phs 6.8 and 7.4, as determined radiometrically. the mics at ph 7.4 were about 1 to 2 dilutions lower than those observed at ph 6.8. in terms of the highest to the lowest activity, the three antibiotics could be classified as follows: clarithromycin > hmr 3 ... | 2000 | 10991870 |
| adjuvant activity of monophosphoryl lipid a for nasal and oral immunization with soluble or liposome-associated antigen. | the effectiveness of monophosphoryl lipid a (mpl) as a mucosal adjuvant was investigated following oral or intranasal (i.n.) administration of an aqueous adjuvant formulation of mpl (mpl-af) added to soluble antigen or liposomal antigen or incorporated into liposomal antigen membranes. groups of balb/c female mice were immunized with 50 to 100 microg of free or liposomal streptococcus mutans crude glucosyltransferase (c-gtf) with or without mpl-af added to the vaccine or incorporated into the li ... | 2000 | 10992447 |
| campylobacter fetus sap inversion occurs in the absence of reca function. | phase variation of campylobacter fetus surface layer proteins (slps) occurs by inversion of a 6.2-kb dna segment containing the unique sap promoter, permitting expression of a single slp-encoding gene. previous work has shown that the c. fetus sap inversion system is reca dependent. when we challenged a pregnant ewe with a reca mutant of wild-type c. fetus (strain 97-211) that expressed the 97-kda slp, 15 of the 16 ovine-passaged isolates expressed the 97-kda protein. however, one strain (97-209 ... | 2000 | 10992468 |
| protective antigen-mediated antibody response against a heterologous protein produced in vivo by bacillus anthracis. | bacillus anthracis secretes a lethal toxin composed of two proteins, the lethal factor (lf) and the protective antigen (pa), which interact within the host or in vitro at the surfaces of eukaryotic cells. immunization with attenuated b. anthracis strains induces an antibody response against pa and lf. the lf-specific response is potentiated by the binding of lf to pa. in this study, we investigated the capacity of pa to increase the antibody response against a foreign antigen. we constructed a c ... | 2000 | 10992478 |
| carbohydrate biopolymers enhance antibody responses to mucosally delivered vaccine antigens. | we have evaluated the ability of two carbohydrate biopolymers, chitosan and gellan, to enhance antibody responses to subunit influenza virus vaccines delivered to the respiratory tracts of mice. groups of mice were vaccinated three times intranasally (i.n.) with 10 microg of purified influenza b/panama virus surface antigens (psas), which consist of hemagglutinin (ha) and neuraminidase (na), either alone or admixed with chitosan or gellan solutions. separate groups were vaccinated subcutaneously ... | 2000 | 10992483 |
| modulation of neutrophil chemokine receptors by staphylococcus aureus supernate. | in a previous study, we showed that staphylococcus aureus supernate (sas) is a potent agonist for both neutrophils and mononuclear cells. to further investigate the immunomodulating effects of sas, the effect on different neutrophil receptors was studied. expression of various neutrophil receptors, before and after treatment with sas, was quantified by flow cytometry. we found that sas treatment of neutrophils resulted in a specific and total downregulation of the c5a and the fmlp receptor, both ... | 2000 | 10992501 |
| comparison of abilities of salmonella enterica serovar typhimurium aroa arod and aroa htra mutants to act as live vectors. | we compared the ability of salmonella enterica serovar typhimurium sl1344 aroa arod (brd509) and aroa htra (brd807) mutants to act as live vectors for delivery of fragment c of tetanus toxin (frgc). frgc was expressed in these strains from either ptetnir15 or ptethtra1. brd509frgc(+) strains elicited approximately 2-log-higher serum anti-frgc antibody titers than brd807frgc(+) strains. all mice immunized with brd807ptethtra1, brd509ptethtra1, and brd509ptetnir15 (but not brd807ptetnir15) were pr ... | 2000 | 10992518 |
| comparison of o-antigen gene clusters of escherichia coli (shigella) sonnei and plesiomonas shigelloides o17: sonnei gained its current plasmid-borne o-antigen genes from p. shigelloides in a recent event. | escherichia coli sonnei has an o antigen identical to that of plesiomonas shigelloides o17, and its o-antigen gene cluster is located on a plasmid. by sequencing the chromosomal o-antigen gene cluster of p. shigelloides o17 and comparing it with that of sonnei, we showed that sonnei gained its o-antigen genes recently. | 2000 | 10992522 |
| intrinsic constraint on plasmablast growth and extrinsic limits of plasma cell survival. | b cells recruited into splenic antibody responses grow exponentially, either in extrafollicular foci as plasmablasts, or in follicles where they form germinal centers. both responses yield plasma cells. although many splenic plasma cells survive <3 d, some live much longer. this study shows that early plasma cell death relates to a finite capacity of the spleen to sustain plasma cells rather than a life span endowed by the cell's origin or the quality of antibody it produces. antibody responses ... | 2000 | 10993912 |
| pertussis infection in fully vaccinated children in day-care centers, israel. | we tested 46 fully vaccinated children in two day-care centers in israel who were exposed to a fatal case of pertussis infection. only two of five children who tested positive for bordetella pertussis met the world health organization's case definition for pertussis. vaccinated children may be asymptomatic reservoirs for infection. | 2000 | 10998384 |
| new virulence-activated and virulence-repressed genes identified by systematic gene inactivation and generation of transcriptional fusions in bordetella pertussis. | an in silico scan of the partially completed genome sequence of bordetella pertussis and analyses of transcriptional fusions generated with a new integrational vector were used to identify new potential virulence genes. the genes encoding a putative siderophore receptor, adhesins, and an autotransporter protein appeared to be regulated in a manner similar to bordetella virulence genes by the global virulence regulator bvgas. in contrast, the gene encoding a putative intimin-like protein appeared ... | 2000 | 11004193 |
| phenotypic analysis of peripheral cd4+ cd8+ t cells in the rat. | among peripheral t cells, the expression of cd4 and cd8 is almost mutually exclusive. however, here we show, using flow cytometric analysis, that ex vivo approximately 6% of rat t cells stained for both cd4 and cd8. these double positive cells were also detected by confocal microscopy. only around 50% of double positive cells expressed the cd8beta chain, the remaining cells expressed the cd8alpha chain alone. double positive cells were blast-like with a phenotype, distinct from that of either cd ... | 2000 | 11012770 |
| the lipid a region of lipopolysaccharides from rhizobiaceae activates bone marrow granulocytes from lipopolysaccharide-hyporesponsive c3h/hej and c57bl/10sccr mice. | we established in previous studies that the binding of salmonella lipopolysaccharide (lps) to constitutive receptors of low affinity triggers the expression of the inducible lps-binding molecule cd14 in bone marrow cells (bmc) of c3h/heou mice, but not in bmc from c3h/hej mice. we show in this study that bmc from c3h/hej and c57bl/10sccr mice do not express cd14 after exposure to lpss from salmonella enterica and bordetella pertussis, but do express this marker when treated with several lpss fro ... | 2000 | 11012780 |
| transfer of palmitate from phospholipids to lipid a in outer membranes of gram-negative bacteria. | regulated covalent modifications of lipid a are implicated in virulence of pathogenic gram-negative bacteria. the salmonella typhimurium phop/phoq-activated gene pagp is required both for biosynthesis of hepta-acylated lipid a species containing palmitate and for resistance to cationic anti-microbial peptides. palmitoylated lipid a can also function as an endotoxin antagonist. we now show that pagp and its escherichia coli homolog (crca) encode an unusual enzyme of lipid a biosynthesis localized ... | 2000 | 11013210 |
| polymorphism in bordetella pertussis pertactin and pertussis toxin virulence factors in the united states, 1935-1999. | to elucidate the potential role of the etiologic agent in recent increases of pertussis incidence in the united states, we studied the polymorphism in pertactin and pertussis toxin, which are bordetella pertussis proteins important for pathogenesis and immunity. we sequenced regions of their genes (prn and ptx) in 152 b. pertussis strains isolated from 1935 through 1999 and identified 2 prn sequences: prn1 (old), observed continuously since 1935, and prn2 (new), not recognized until 1981 but see ... | 2000 | 11023463 |
| interference of antibacterial agents with phagocyte functions: immunomodulation or "immuno-fairy tales"? | professional phagocytes (polymorphonuclear neutrophils and monocytes/macrophages) are a main component of the immune system. these cells are involved in both host defenses and various pathological settings characterized by excessive inflammation. accordingly, they are key targets for immunomodulatory drugs, among which antibacterial agents are promising candidates. the basic and historical concepts of immunomodulation will first be briefly reviewed. phagocyte complexity will then be unravelled ( ... | 2000 | 11023961 |
| impaired gamma interferon responses against parvovirus b19 by recently infected children. | parvovirus b19 is the causative agent of "fifth disease" of childhood. it has been implicated in a variety of conditions, including unsuccessful pregnancy and rheumatoid arthritis, and is a potential contaminant of blood products. there has been little study of immunity to parvovirus b19, and the exact nature of the protective humoral and cell-mediated immune response is unclear. immune responses to purified virus capsid proteins, vp1 and vp2, were examined from a cohort of recently infected chi ... | 2000 | 11024117 |
| co-expression of the bordetella pertussis leader peptidase i results in enhanced processing and expression of the pertussis toxin s1 subunit in escherichia coli. | bordetella pertussis is the causative agent of whooping cough. traditional vaccines against this disease are inherently reactogenic, thus research is currently focussed on the production of less reactive, acellular vaccines. expression of candidate antigens for these vaccines in escherichia coli would be preferable, however, several b. pertussis antigens undergo incorrect post-translational processing in e. coli. the leader peptidase gene (lep) of b. pertussis encodes a protein of 294 amino acid ... | 2000 | 11024260 |
| the haemophilus influenzae hia adhesin is an autotransporter protein that remains uncleaved at the c terminus and fully cell associated. | nontypeable haemophilus influenzae is a gram-negative commensal organism that is commonly associated with localized respiratory tract disease. the pathogenesis of disease begins with colonization of the nasopharynx, a process that likely depends on bacterial adherence to respiratory epithelial cells. hia is the major adhesin expressed by a subset of nontypeable h. influenzae strains and promotes efficient adherence to a variety of human epithelial cell lines. based on previous work, hia is trans ... | 2000 | 11029419 |
| discovery, purification, and characterization of a temperate transducing bacteriophage for bordetella avium. | we discovered and characterized a temperate transducing bacteriophage (ba1) for the avian respiratory pathogen bordetella avium. ba1 was initially identified along with one other phage (ba2) following screening of four strains of b. avium for lysogeny. of the two phage, only ba1 showed the ability to transduce via an allelic replacement mechanism and was studied further. with regard to host range, ba1 grew on six of nine clinical isolates of b. avium but failed to grow on any tested strains of b ... | 2000 | 11029434 |
| nonspecific adherence by actinobacillus actinomycetemcomitans requires genes widespread in bacteria and archaea. | the gram-negative coccobacillus, actinobacillus actinomycetemcomitans, is the putative agent for localized juvenile periodontitis, a particularly destructive form of periodontal disease in adolescents. this bacterium has also been isolated from a variety of other infections, notably endocarditis. fresh clinical isolates of a. actinomycetemcomitans form tenacious biofilms, a property likely to be critical for colonization of teeth and other surfaces. here we report the identification of a locus o ... | 2000 | 11029439 |
| [genetic evolution under vaccine pressure: the bordetella pertussis model]. | a possible genetic selective pressure related to the long-term use of vaccines has been the object of recent theoretical thought and publications. for more than thirty years, an effective vaccine has been in use against whooping cough on a wide scale basis in several countries. thus, the bordetella pertussis model may contribute to the analysis of an evolutionary risk linked to the vaccine. to maintain and improve the control of whooping cough, better vaccination coverage must be achieved in cou ... | 2000 | 11030058 |
| acylation of lysine 983 is sufficient for toxin activity of bordetella pertussis adenylate cyclase. substitutions of alanine 140 modulate acylation site selectivity of the toxin acyltransferase cyac. | the capacity of adenylate cyclase toxin (act) to penetrate into target cells depends on post-translational fatty-acylation by the acyltransferase cyac, which can palmitoylate the conserved lysines 983 and 860 of act. here, the in vivo acylating capacity of a set of mutated cyac acyltransferases was characterized by two-dimensional gel electrophoresis and mass spectrometric analyses of the act product. substitutions of the potentially catalytic serine 20 and histidine 33 residues ablated acylatin ... | 2001 | 11031260 |
| secretion of rtx leukotoxin by actinobacillus actinomycetemcomitans. | actinobacillus actinomycetemcomitans, the etiologic agent for localized juvenile periodontitis and certain other human infections, such as endocarditis, expresses a leukotoxin that acts on polymorphonuclear leukocytes and macrophages. leukotoxin is a member of the highly conserved repeat toxin (rtx) family of bacterial toxins expressed by a variety of pathogenic bacteria. while the rtx toxins of other bacterial species are secreted, the leukotoxin of a. actinomycetemcomitans is thought to remain ... | 2000 | 11035711 |
| the locus of enterocyte effacement (lee)-encoded regulator controls expression of both lee- and non-lee-encoded virulence factors in enteropathogenic and enterohemorrhagic escherichia coli. | regulation of virulence gene expression in enteropathogenic escherichia coli (epec) and enterohemorrhagic e. coli (ehec) is incompletely understood. in epec, the plasmid-encoded regulator per is required for maximal expression of proteins encoded on the locus of enterocyte effacement (lee), and a lee-encoded regulator (ler) is part of the per-mediated regulatory cascade upregulating the lee2, lee3, and lee4 promoters. we now report that ler is essential for the expression of multiple lee-located ... | 2000 | 11035714 |
| genetic and functional analysis of a pmra-pmrb-regulated locus necessary for lipopolysaccharide modification, antimicrobial peptide resistance, and oral virulence of salmonella enterica serovar typhimurium. | the two-component regulatory system pmra-pmrb confers resistance of salmonella spp. to cationic antimicrobial peptides (ap) such as polymyxin (pm), bactericidal/permeability-increasing protein, and azurocidin. this resistance occurs by transcriptional activation of two loci termed pmre and pmrhfijklm. both pmre and pmrhfijklm produce products required for the biosynthesis of lipid a with 4-aminoarabinose (ara4n). ara4n addition creates a more positively charged lipopolysaccharide (lps) and thus ... | 2000 | 11035717 |
| detection and characterization of autoagglutination activity by campylobacter jejuni. | in several gram-negative bacterial pathogens, autoagglutination (aag) activity is a marker for interaction with host cells and virulence. campylobacter jejuni strains also show aag, but this property varies considerably among strains. to examine the characteristics of c. jejuni aag, we developed a quantitative in vitro assay. for strain 81-176, which shows high aag, activity was optimal for cells grown for < or = 24 h, was independent of growth temperature, and was best measured for cells suspen ... | 2000 | 11035721 |
| tonb is required for intracellular growth and virulence of shigella dysenteriae. | to assess the importance of tonb-dependent iron transport systems to growth of shigella in vivo, a tonb mutant of shigella dysenteriae was isolated and tested in cultured cells. the tonb mutant invaded epithelial cells, but did not form plaques in confluent monolayers of henle cells, indicating an inability of this mutant to spread from cell to cell. the rate of intracellular multiplication of the tonb mutant was reduced significantly compared to that of the wild type. the loss of virulence in t ... | 2000 | 11035742 |
| bordetella pertussis adenylate cyclase toxin: a vehicle to deliver cd8-positive t-cell epitopes into antigen-presenting cells. | 2000 | 11036662 | |
| spt5 and spt6 are associated with active transcription and have characteristics of general elongation factors in d. melanogaster. | the spt4, spt5, and spt6 proteins are conserved throughout eukaryotes and are believed to play critical and related roles in transcription. they have a positive role in transcription elongation in saccharomyces cerevisiae and in the activation of transcription by the hiv tat protein in human cells. in contrast, a complex of spt4 and spt5 is required in vitro for the inhibition of rna polymerase ii (pol ii) elongation by the drug drb, suggesting also a negative role in vivo. to learn more about t ... | 2000 | 11040216 |
| characterization of a novel outer membrane hemin-binding protein of porphyromonas gingivalis. | porphyromonas gingivalis is a gram-negative, anaerobic coccobacillus that has been implicated as a major etiological agent in the development of chronic periodontitis. in this paper, we report the characterization of a protein, ihtb (iron heme transport; formerly designated pga30), that is an outer membrane hemin-binding protein potentially involved in iron assimilation by p. gingivalis. ihtb was localized to the cell surface of p. gingivalis by western blot analysis of a sarkosyl-insoluble oute ... | 2000 | 11053391 |
| genes for the type iv secretion system in an intracellular symbiont, wolbachia, a causative agent of various sexual alterations in arthropods. | wolbachia species are intracellular bacteria known to cause reproductive abnormalities in their hosts. in this study, we identified wolbachia genes encoding homologs to the type iv secretion system by which many pathogenic bacteria secrete macromolecules. the genes identified encoded most of the essential components of the secretion system and were cotranscribed as an operon. | 2000 | 11053403 |
| characterization of fimn, a new bordetella bronchiseptica major fimbrial subunit gene. | fimbrial proteins play an important role in the binding of bordetella bronchiseptica to mammalian cells, an event that is key to the pathogenesis of this organism. the fimbrial phenotype of b. bronchiseptica isolates is usually defined serologically by fim2 and fim3 antigens. in this study, a previously unidentified fimbrial gene, fimn, was cloned and sequenced. the identity of fimn is based on several observations. the predicted fimn protein has 59.4 and 52. 2% homology with b. bronchiseptica f ... | 2000 | 11054544 |
| ingested blood contributes to the specificity of the symbiosis of aeromonas veronii biovar sobria and hirudo medicinalis, the medicinal leech. | hirudo medicinalis, the medicinal leech, usually carries in its digestive tract a pure culture of aeromonas veronii bv. sobria. such specificity is unusual for digestive tracts that are normally colonized by a complex microbial consortium. important questions for the symbiotic interaction and for the medical application after microvascular surgery are whether other bacteria can proliferate or at least persist in the digestive tract of h. medicinalis and what factors contribute to the reported sp ... | 2000 | 11055917 |
| monoarticular antigen-induced arthritis leads to pronounced bilateral upregulation of the expression of neurokinin 1 and bradykinin 2 receptors in dorsal root ganglion neurons of rats. | statement of findings: this study describes the upregulation of neurokinin 1 and bradykinin 2 receptors in dorsal root ganglion (drg) neurons in the course of antigen-induced arthritis (aia) in the rat knee. in the acute phase of aia, which was characterized by pronounced hyperalgesia, there was a substantial bilateral increase in the proportion of lumbar drg neurons that express neurokinin 1 receptors (activated by substance p) and bradykinin 2 receptors. in the chronic phase the upregulation o ... | 2000 | 11056677 |
| enhanced expression of genes involved in coagulation and fibrinolysis in murine arthritis. | statement of findings: we have analyzed the pattern of procoagulant and fibrinolytic gene expression in affected joints during the course of arthritis in two murine models. in both models, we found an increased expression of tissue factor, tissue factor pathway inhibitor, urokinase plasminogen activator, and plasminogen activator inhibitor 1, as well as thrombin receptor. the observed pattern of gene expression tended to favor procoagulant activity, and this pattern was confirmed by functional a ... | 2000 | 11056680 |
| detection of legionella pneumophila using a real-time pcr hybridization assay. | a real-time pcr hybridization assay for legionella pneumophila is described; the assay uses lightcycler (idaho technology) methodology to specifically detect 2.5 cfu/reaction, equivalent to 1,000 cfu/liter of starting water sample. the assay, including dna extraction and confirmation of product identity, is completed within 90 min of receipt of a sample. | 2000 | 11060093 |
| influenza virus lung infection protects from respiratory syncytial virus-induced immunopathology. | the effect of infection history is ignored in most animal models of infectious disease. the attachment protein of respiratory syncytial virus (rsv) induces t helper cell type 2-driven pulmonary eosinophilia in mice similar to that seen in the failed infant vaccinations in the 1960s. we show that previous influenza virus infection of mice: (a) protects against weight loss, illness, and lung eosinophilia; (b) attenuates recruitment of inflammatory cells; and (c) reduces cytokine secretion caused b ... | 2000 | 11067880 |
| modulation of innate and acquired immune responses by escherichia coli heat-labile toxin: distinct pro- and anti-inflammatory effects of the nontoxic ab complex and the enzyme activity. | we have examined the roles of enzyme activity and the nontoxic ab complex of heat-labile toxin (lt) from escherichia coli on its adjuvant and immunomodulatory properties. ltk63, an lt mutant that is completely devoid of enzyme activity, enhanced th1 responses to coinjected ags at low adjuvant dose. in contrast, ltr72, a partially detoxified mutant, enhanced th2 responses and when administered intranasally to mice before infection with bordetella pertussis suppressed th1 responses and delayed bac ... | 2000 | 11067933 |
| four genes are required for the system ii cytochrome c biogenesis pathway in bordetella pertussis, a unique bacterial model. | unlike other cytochromes, c-type cytochromes have two covalent bonds formed between the two vinyl groups of haem and two cysteines of the protein. this haem ligation requires specific assembly proteins in prokaryotes or eukaryotic mitochondria and chloroplasts. here, it is shown that bordetella pertussis is an excellent bacterial model for the widespread system ii cytochrome c synthesis pathway. mutations in four different genes (ccsa, ccsb, ccsx and dipz) result in b. pertussis strains unable t ... | 2000 | 11069671 |
| invb is a type iii secretion chaperone specific for sspa. | a wide variety of gram-negative bacteria utilize a specialized apparatus called the type iii secretion system (ttss) to translocate virulence factors directly into the cytoplasm of eukaryotic cells. these translocated effectors contribute to the pathogen's ability to infect and replicate within plant and animal hosts. the amino terminus of effector proteins contains sequences that are necessary and sufficient for both secretion and translocation by ttss. portions of these sequences contain bindi ... | 2000 | 11073906 |
| multicomponent transcriptional regulation at the complex promoter of the exopolysaccharide i biosynthetic operon of ralstonia solanacearum. | high-level transcription of eps, an operon encoding biosynthesis of an exopolysaccharide virulence factor of the phytopathogen ralstonia (pseudomonas) solanacearum, requires the products of at least seven regulatory genes (phca, phcb, xpsr, vsra-vsrd, and vsrb-vsrc), which are organized in three converging signal transduction cascades. because xpsr and the vsrb-vsrc two-component system are the most downstream cascade components required for activation of eps, we explored how these components co ... | 2000 | 11073909 |
| novel role for an hpt domain in stabilizing the phosphorylated state of a response regulator domain. | two-component regulatory systems that utilize a multistep phosphorelay mechanism often involve a histidine-containing phosphotransfer (hpt) domain. these hpt domains serve an essential role as histidine-phosphorylated protein intermediates during phosphoryl transfer from one response regulator domain to another. in saccharomyces cerevisiae, the ypd1 protein facilitates phosphoryl transfer from a hybrid sensor kinase, sln1, to two distinct response regulator proteins, ssk1 and skn7. because the p ... | 2000 | 11073911 |
| catalase-peroxidases of legionella pneumophila: cloning of the kata gene and studies of kata function. | legionella pneumophila, the causative organism of legionnaires' pneumonia, contains two enzymes with catalatic and peroxidatic activity, kata and katb. to address the issue of redundant, overlapping, or discrete in vivo functions of highly homologous catalase-peroxidases, the gene for kata was cloned and its function was studied in l. pneumophila and escherichia coli and compared with prior studies of katb in this laboratory. kata is induced during exponential growth and is the predominant perox ... | 2000 | 11073912 |
| maturation of incp pilin precursors resembles the catalytic dyad-like mechanism of leader peptidases. | the pilus subunit, the pilin, of conjugative incp pili is encoded by the trbc gene. incp pilin is composed of 78 amino acids forming a ring structure (r. eisenbrandt, m. kalkum, e.-m. lai, c. i. kado, and e. lanka, j. biol. chem. 274:22548-22555, 1999). three enzymes are involved in maturation of the pilin: lepb of escherichia coli for signal peptide removal and a yet-unidentified protease for removal of 27 c-terminal residues. both enzymes are chromosome encoded. finally, the inner membrane-ass ... | 2000 | 11073921 |
| structure and sequence analysis of yersinia yada and moraxella uspas reveal a novel class of adhesins. | the non-fimbrial adhesins, yada of enteropathogenic yersinia species, and uspa1 and uspa2 of moraxella catarrhalis, are established pathogenicity factors. in electron micrographs, both surface proteins appear as distinct 'lollipop'-shaped structures forming a novel type of surface projection on the outer membranes. these structures, amino acid sequence analysis of these molecules and yada gene manipulation suggest a tripartite organization: an n-terminal oval head domain is followed by a putativ ... | 2000 | 11080146 |
| impa, a gene coding for an inner membrane protein, influences colonial morphology of actinobacillus actinomycetemcomitans. | directed mutagenesis of a gene coding for a membrane protein of the periodontopathogen actinobacillus actinomycetemcomitans was achieved by conjugation. the gene was disrupted by insertion of an antibiotic cassette into a unique endonuclease restriction sequence engineered by inverse pcr. the disrupted gene was cloned into a conjugative plasmid and transferred from escherichia coli to a. actinomycetemcomitans. the allelic replacement mutation resulted in the loss of a 22-kda inner membrane prote ... | 2000 | 11083768 |
| multiple roles for bordetella lipopolysaccharide molecules during respiratory tract infection. | bordetella pertussis, bordetella parapertussis, and bordetella bronchiseptica are closely related subspecies that cause respiratory tract infections in humans and other mammals and express many similar virulence factors. their lipopolysaccharide (lps) molecules differ, containing either a complex trisaccharide (b. pertussis), a trisaccharide plus an o-antigen-like repeat (b. bronchiseptica), or an altered trisaccharide plus an o-antigen-like repeat (b. parapertussis). deletion of the wlb locus r ... | 2000 | 11083787 |
| hemin-binding surface protein from bartonella quintana. | bartonella quintana, the agent of trench fever and a cause of endocarditis and bacillary angiomatosis in humans, has the highest reported in vitro hemin requirement for any bacterium. we determined that eight membrane-associated proteins from b. quintana bind hemin and that a approximately 25-kda protein (hbpa) was the dominant hemin-binding protein. like many outer membrane proteins, hbpa partitions to the detergent phase of a triton x-114 extract of the cell and is heat modifiable, displaying ... | 2000 | 11083791 |
| phagosome acidification has opposite effects on intracellular survival of bordetella pertussis and b. bronchiseptica. | bordetella pertussis is readily killed after uptake by professional phagocytes, whereas its close relative bordetella bronchiseptica is not and can persist intracellularly for days. phagocytosis of members of either species by a mouse macrophage cell line results in transport of the bacteria to a phagosomal compartment positive for the lysosome-associated membrane protein 1, the protease cathepsin d, and the late endosomal vacuolar proton-pumping atpase but negative for the early endosome antige ... | 2000 | 11083829 |
| mig-14 is a horizontally acquired, host-induced gene required for salmonella enterica lethal infection in the murine model of typhoid fever. | we have characterized a host-induced virulence gene, mig-14, that is required for fatal infection in the mouse model of enteric fever. mig-14 is present in all salmonella enterica subspecies i serovars and maps to a region of the chromosome that appears to have been acquired by horizontal transmission. a mig-14 mutant replicated in host tissues early after infection but was later cleared from the spleens and livers of infected animals. bacterial clearance by the host occurred concomitantly with ... | 2000 | 11083839 |
| identification of genes present specifically in a virulent strain of klebsiella pneumoniae. | klebsiella pneumoniae is a common cause of septicemia and urinary tract infections. the pcr-supported genomic subtractive hybridization was employed to identify genes specifically present in a virulent strain of k. pneumoniae. analysis of 25 subtracted dna clones has revealed 19 distinct nucleotide sequences. two of the sequences were found to be the genes encoding the transposase of tn3926 and a capsule polysaccharide exporting enzyme. three sequences displayed moderate homology with bvgas, whi ... | 2000 | 11083844 |
| neutralizing antibodies to adenylate cyclase toxin promote phagocytosis of bordetella pertussis by human neutrophils. | a previous study showed that opsonization with human immune serum could either promote or antagonize phagocytosis of bordetella pertussis by human neutrophils depending on whether the bacteria expressed adenylate cyclase toxin. opsonization of the wild-type strain inhibited phagocytosis relative to unopsonized controls. in contrast, mutants lacking adenylate cyclase toxin were efficiently phagocytosed when opsonized with human immune serum. in this study, we examined opsonization in the presence ... | 2000 | 11083845 |
| characterization of bactericidal immune responses following vaccination with acellular pertussis vaccines in adults. | sera from six adults, collected before and after acellular pertussis vaccination, and from a placebo control were examined for the ability to elicit two bactericidal immune defenses, (i) antibody-dependent complement-mediated bacterial lysis and (ii) opsonization and phagocytosis by human neutrophils. the samples were chosen based on low preimmunization titers and strong postimmunization responses to various combinations of vaccine antigens. all but two prevaccination samples demonstrated activi ... | 2000 | 11083851 |
| insulinotropic toxins as molecular probes for analysis of glucagon-likepeptide-1 receptor-mediated signal transduction in pancreatic beta-cells. | cholera toxin, pertussis toxin, mastoparan, maitotoxin, and alpha-latrotoxin are complex protein or polyether-based toxins of bacterial, insect, or phytoplankton origin that act with high potency at the endocrine pancreas to stimulate secretion of insulin from beta-cells located in the islets of langerhans. the remarkable insulinotropic properties of these toxins have attracted considerable attention by virtue of their use as selective molecular probes for analyses of beta-cell stimulus-secretio ... | 2000 | 11086221 |
| the transcriptional responses of respiratory epithelial cells to bordetella pertussis reveal host defensive and pathogen counter-defensive strategies. | bordetella pertussis, the causative agent of whooping cough, has many well-studied virulence factors and a characteristic clinical presentation. despite this information, it is not clear how b. pertussis interaction with host cells leads to disease. in this study, we examined the interaction of b. pertussis with a human bronchial epithelial cell line (beas-2b) and measured host transcriptional profiles by using high-density dna microarrays. the early transcriptional response to this pathogen is ... | 2000 | 11087813 |
| immediate inhibition by oral l-ephedrine of passive cutaneous anaphylaxis of rats: indirect inhibition of anaphylactic chemical mediator release from the mast cell. | we previously reported that oral l-ephedrine showed extraordinarily rapid inhibition of 48-h passive cutaneous anaphylaxis (pca) in rats. in the present study, in vivo and in vitro experiments were performed to elucidate a possible mechanism for the inhibition. | 2000 | 11089909 |
| partial to complete antagonism by putative antagonists at the wild-type alpha(2c)-adrenoceptor based on kinetic analyses of agonist:antagonist interactions. | 1. activation of the recombinant human alpha(2c)-adrenoceptor (alpha(2c) ar) by (-)-adrenaline in cho-k1 cells transiently co-expressing a chimeric g(alpha q/i1) protein induced a rapid, transient ca(2+) response with a high-magnitude followed by a low-magnitude phase which continued throughout the recorded time period (15 min). 2. activation of the alpha(2c) ar by various alpha(2) ar agonists revealed the following rank order of high-magnitude ca(2+) response [e(max) (%) versus 10 microm (-)-ad ... | 2000 | 11090111 |
| sensitive genetic screen for protease activity based on a cyclic amp signaling cascade in escherichia coli. | we describe a genetic system that allows in vivo screening or selection of site-specific proteases and of their cognate-specific inhibitors in escherichia coli. this genetic test is based on the specific proteolysis of a signaling enzyme, the adenylate cyclase (ac) of bordetella pertussis. as a model system we used the human immunodeficiency virus (hiv) protease. when an hiv protease processing site, p5, was inserted in frame into the ac polypeptide, the resulting acp5 protein retained enzymatic ... | 2000 | 11092869 |
| comparison between histopathologic findings and indocyanine green angiographic findings in lewis rats with experimental autoimmune uveoretinitis. | recently, indocyanine green angiography (ia) was used to examine chorioretinal circulation in posterior uveitis in humans, and abnormal ia findings were reported. however, choroidal pathologic examination in conjunction with these abnormal ia findings has rarely been done. experimental autoimmune uveoretinitis (eau) is a model for posterior uveitis in humans. the purpose of this study was to correlate abnormal ia findings in lewis rats with eau with pathologic findings. | 2000 | 11094176 |
| the bvg accessory factor (baf) enhances pertussis toxin expression in escherichia coli and is essential for bordetella pertussis viability. | pertussis toxin expression in the gram-negative respiratory pathogen, bordetella pertussis, is regulated by the bvgas two-component system. previous studies suggested that an additional gene encoding a bvg accessory factor (baf) was required, along with bvgas, for expression of a ptx-lacz fusion in escherichia coli grown in rich medium. however, other studies showed that bvgas is sufficient for ptx-lacz expression in minimal medium. here we show that baf acts with bvgas to further increase ptx-l ... | 2000 | 11094274 |
| pushing the limits of cellular microbiology: microarrays to study bacteria-host cell intimate contacts. | 2000 | 11095701 | |
| restriction endonuclease analysis discriminates bordetella bronchiseptica isolates. | one hundred ninety-five bordetella bronchiseptica isolates from 12 different host species worldwide were characterized by restriction enzyme analysis (rea). these isolates had previously been categorized into 19 pvuii ribotypes. twenty restriction endonucleases were evaluated for use in rea. digestion of chromosomal dna with hinfi, followed by submarine electrophoresis in agarose gels and staining with ethidium bromide, produced dna fragments in the 4.0- to 10-kb range, which readily discriminat ... | 2000 | 11101569 |
| rapid-cycle pcr method to detect bordetella pertussis that fulfills all consensus recommendations for use of pcr in diagnosis of pertussis. | no standardized pcr method is available for the laboratory diagnosis of the pertussis syndrome. consensus recommendations for the use of pcr in the diagnosis of bordetella pertussis infections have been proposed, and the aim of this study was to develop a method that fulfills all of these criteria. a rapid-cycle shared-primer pcr method with a microwell format and probe hybridization detection step (por) was developed using novel oligonucleotides targeted to the outer membrane porin gene (bordet ... | 2000 | 11101586 |
| virulence factors of helicobacter pylori responsible for gastric diseases in mongolian gerbil. | helicobacter pylori infection induces various gastroduodenal diseases. we examined the role of two genes, vaca and cage, in the gastric pathogenesis induced by h. pylori using a long-term (62 wk) animal model. reportedly, both genes are associated with the virulence of h. pylori: vaca encodes vacuolating cytotoxin, and cage, with other genes in the cag pathogenicity islands, encodes a type iv secretion system. mongolian gerbils were challenged in this study by a wild-type tn2 strain and its isog ... | 2000 | 11104802 |
| the cxcr4 agonist ligand stromal derived factor-1 maintains high affinity for receptors in both galpha(i)-coupled and uncoupled states. | the alpha chemokine receptor cxcr4 and its only characterized chemokine ligand, stromal cell-derived factor-1 (sdf-1), are postulated to be important in the development of the b-cell arm of the immune system. in addition, cxcr4 is a critical coreceptor in support of viral entry by t-cell line tropic strains (x4) of the human immunodeficiency virus type 1 (hiv-1), viral variants which predominate in some infected individuals in end stage disease. sdf-1 can block x4-tropic hiv-1 infection of cd4+ ... | 2000 | 11104827 |
| identification of motifs in cholera toxin a1 polypeptide that are required for its interaction with human adp-ribosylation factor 6 in a bacterial two-hybrid system. | the latent adp-ribosyltransferase activity of cholera toxin (ct) that is activated after proteolytic nicking and reduction is associated with the ct a1 subunit (cta1) polypeptide. this activity is stimulated in vitro by interaction with eukaryotic proteins termed adp-ribosylation factors (arfs). we analyzed this interaction in a modified bacterial two-hybrid system in which the t18 and t25 fragments of the catalytic domain of bordetella pertussis adenylate cyclase were fused to cta1 and human ar ... | 2000 | 11106366 |
| involvement of il-6, apart from its role in immunity, in mediating a chronic response during experimental arthritis. | interleukin-6 (il-6) is highly produced during arthritis but its exact function is still unknown. in this study we examined if il-6, apart from its role in immunity, was involved in the local inflammatory response in experimental arthritis. il-6 deficient (il-6(-/-)) and wild-type mice were first compared in the antigen-induced arthritis model. il-6 deficiency resulted in a mild, transient inflammation whereas wild-type mice developed a chronic, destructive synovitis. wild-type mice immunized wi ... | 2000 | 11106580 |
| [restriction analysis of bordetella pertussis dna isolated from patients with whooping cough in 1968 and 1995-98 and b. pertussis used for production of national vaccine strains]. | the genotypic and serotypic analysis of b. pertussis strains isolated from the nasopharynx of children with whooping cough in the years 1968 and 1995-98 and b. pertussis vaccine strains was the aim of this study. the genotyping of the examined strains was done by electrophoretic division of dna in pulsed field. the 3 types (a, b, c) and 2 subtypes (a1 and a2) of dna restriction patterns were determined for the b. pertussis strains isolated in 1968. the 2 types (d and e) and 10 subtypes (d1-d10) ... | 2000 | 11107785 |
| genomics of bordetella pertussis toxins. | bordetella pertussis, the etiologic agent of whooping cough, produces numerous toxins including pertussis toxin (ptx), adenylate cyclase toxin (ac), dermonecrotic toxin (dnt) and tracheal cytotoxin (tct). ptx is composed of five different subunits organised in a typical a-b type structure of which the a part possesses an enzymatic adp-ribosyltransferase activity and the b moiety expresses receptor-binding activity. the secretion of this toxin requires nine other genes (ptl) organised in an opero ... | 2000 | 11111902 |
| structure-function relationships in the bvg and evg two-component phosphorelay systems. | the unorthodox two-component phosphorelay systems bvgas and evgas of bordetella pertussis and e. coli, respectively, are suitable model systems to investigate the molecular basis of signalling specificity, because, despite their high relatedness on the sequence level, they do not cross-talk to each other. we could show that the two systems belong to the obligate type of phosphorelay systems and that signalling specificity is mediated by the hpt modules of the histidine kinases and the receiver d ... | 2000 | 11111905 |
| adenylate cyclase toxin from bordetella pertussis: current concepts and problems in the study of toxin functions. | adenylate cyclase (ac) toxin produced by bordella pertussis and other bordella species is a virulence factor and protective antigen with novel properties and activities, which make it attractive as a prototype toxin for study of membrane insertion and delivery to the target cell interior. it is unique among rtx toxins in that it possesses enzymatic (adenylate cyclase) activity, as well as the capacity to create an ion-permeable pore in target cell membranes and lyse erythrocytes. the current iss ... | 2000 | 11111907 |
| bordetella pertussis adenylate cyclase toxin as a tool to analyze molecular interactions in a bacterial two-hybrid system. | bordetella pertussis secretes a calmodulin-activated adenylate cyclase toxin (cyaa) that is able to enter into eukaryotic cells. we took advantage of the modular structure of the catalytic domain of cyaa to design a genetic system that can detect protein-protein interactions in escherichia coli. this bacterial two-hybrid system is based on the functional complementation between two complementary fragments, t25 and t18, of the catalytic domain of cyaa, in an e. coli cya strain. this bacterial two ... | 2000 | 11111924 |
| control of the ferric citrate transport system of escherichia coli: mutations in region 2.1 of the feci extracytoplasmic-function sigma factor suppress mutations in the fecr transmembrane regulatory protein. | transcription of the ferric citrate transport genes is initiated by binding of ferric citrate to the feca protein in the outer membrane of escherichia coli k-12. bound ferric citrate does not have to be transported but initiates a signal that is transmitted by feca across the outer membrane and by fecr across the cytoplasmic membrane into the cytoplasm, where the feci extracytoplasmic-function (ecf) sigma factor becomes active. in this study, we isolated transcription initiation-negative missens ... | 2001 | 11114913 |
| initiation factor 2 of myxococcus xanthus, a large version of prokaryotic translation initiation factor 2. | we have isolated the structural gene for translation initiation factor if2 (infb) from the myxobacterium myxococcus xanthus. the gene (3.22 kb) encodes a 1,070-residue protein showing extensive homology within its g domain and c terminus to the equivalent regions of if2 from escherichia coli. the protein cross-reacts with antibodies raised against e. coli if2 and was able to complement an e. coli infb mutant. the m. xanthus protein is the largest if2 known to date. this is essentially due to a l ... | 2001 | 11114918 |
| characterization of in53, a class 1 plasmid- and composite transposon-located integron of escherichia coli which carries an unusual array of gene cassettes. | further characterization of the genetic environment of the gene encoding the escherichia coli extended-spectrum beta-lactamase, bla(veb-1), revealed the presence of a plasmid-located class 1 integron, in53, which carried eight functional resistance gene cassettes in addition to bla(veb-1). while the aadb and the arr-2 gene cassettes were identical to those previously described, the remaining cassettes were novel: (i) a novel nonenzymatic chloramphenicol resistance gene of the cmla family, (ii) a ... | 2001 | 11114922 |
| vibrio fischeri genes hvna and hvnb encode secreted nad(+)-glycohydrolases. | hvna and hvnb are proteins secreted by vibrio fischeri es114, an extracellular light organ symbiont of the squid euprymna scolopes, that catalyze the transfer of adp-ribose from nad(+) to polyarginine. based on this activity, hvna and hvnb were presumptively designated mono-adp-ribosyltransferases (artases), and it was hypothesized that they mediate bacterium-host signaling. we have cloned hvna and hvnb from strain es114. hvna appears to be expressed as part of a four-gene operon, whereas hvnb i ... | 2001 | 11114931 |
| costs of illness due to bordetella pertussis in families. | to assess costs of pertussis morbidity among families in a community setting. | 2000 | 11115197 |
| enterotoxigenic escherichia coli tiba glycoprotein adheres to human intestine epithelial cells. | enterotoxigenic escherichia coli (etec) is capable of invading epithelial cell lines derived from the human ileum and colon. two separate invasion loci (tia and tib) that direct noninvasive e. coli strains to adhere to and invade cultured human intestine epithelial cells have previously been isolated from the classical etec strain h10407. the tib locus directs the synthesis of tiba, a 104-kda outer membrane glycoprotein. synthesis of tiba is directly correlated with the adherence and invasion ph ... | 2001 | 11119488 |
| silencing and reactivation of urease in yersinia pestis is determined by one g residue at a specific position in the ured gene. | yersinia pestis, the plague agent, is a naturally nonureolytic microorganism, while all other yersinia species display a potent urease activity. in this report we demonstrate that y. pestis harbors a complete urease locus composed of three structural (ureabc) and four accessory (ureefgd) genes. absence of ureolytic activity is due to the presence of one additional g residue in a poly(g) stretch, which introduces a premature stop codon in ured. the presence of the same additional g in eight other ... | 2001 | 11119503 |
| susceptibility to secondary francisella tularensis live vaccine strain infection in b-cell-deficient mice is associated with neutrophilia but not with defects in specific t-cell-mediated immunity. | previous studies have demonstrated a role for b cells, not associated with antibody production, in protection against lethal secondary infection of mice with francisella tularensis live vaccine strain (lvs). however, the mechanism by which b cells contribute to this protection is not known. to study the specific role of b cells during secondary lvs infection, we developed an in vitro culture system that mimics many of the same characteristics of in vivo infection. using this culture system, we s ... | 2001 | 11119506 |
| invasion of human epithelial cells by pseudomonas aeruginosa involves src-like tyrosine kinases p60src and p59fyn. | pseudomonas aeruginosa plays a major role in respiratory tract infections or sepsis in patients with cystic fibrosis or upon suppression of the immune system. several p. aeruginosa strains have been shown to be internalized by human epithelial cells; however, the molecular mechanisms of the invasion process are poorly characterized. here, we show that the internalization of p. aeruginosa into human epithelial cells results in and requires activation of the src-like tyrosine kinases p59fyn and p6 ... | 2001 | 11119516 |
| mapping of binding domains of nontypeable haemophilus influenzae hmw1 and hmw2 adhesins. | nontypeable haemophilus influenzae is an important cause of localized respiratory tract disease, which begins with colonization of the upper respiratory mucosa. in previous work we reported that the nontypeable h. influenzae hmw1 and hmw2 proteins are high-molecular-weight nonpilus adhesins responsible for attachment to human epithelial cells, an essential step in the process of colonization. interestingly, although hmw1 and hmw2 share significant sequence similarity, they display distinct cellu ... | 2001 | 11119519 |
| temperature-regulated protein synthesis by leptospira interrogans. | leptospira interrogans is an important mammalian pathogen. transmission from an environmental source requires adaptations to a range of new environmental conditions in the organs and tissues of the infected host. since many pathogenic bacteria utilize temperature to discern their environment and regulate the synthesis of appropriate proteins, we investigated the effects of temperature on protein synthesis in l. interrogans. bacteria were grown for several days after culture temperatures were shi ... | 2001 | 11119530 |
| legionella pneumophila entry gene rtxa is involved in virulence. | successful parasitism of host cells by intracellular pathogens involves adherence, entry, survival, intracellular replication, and cell-to-cell spread. our laboratory has been examining the role of early events, adherence and entry, in the pathogenesis of the facultative intracellular pathogen legionella pneumophila. currently, the mechanisms used by l. pneumophila to gain access to the intracellular environment are not well understood. we have recently isolated three loci, designated enh1, enh2 ... | 2001 | 11119544 |
| macrolide resistance conferred by base substitutions in 23s rrna. | 2001 | 11120937 | |
| the protective effects of omega-6 fatty acids in experimental autoimmune encephalomyelitis (eae) in relation to transforming growth factor-beta 1 (tgf-beta1) up-regulation and increased prostaglandin e2 (pge2) production. | polyunsaturated fatty acids are known to affect the immune response and administration of the omega-6 fatty acid linoleic acid has been reported to be beneficial in multiple sclerosis (ms) and eae. in this study we have investigated the effects of oral feeding of plant lipid rich in the omega-6 fatty acid gamma-linolenic acid from borago officinalis on acute and relapse disease and the immune response in eae using sjl mice. eae was induced by an encephalitogenic peptide (92-106) of myelin oligod ... | 2000 | 11122253 |
| identification and characterization of bipa, a bordetella bvg-intermediate phase protein. | the bordetella bvgas sensory transduction system has traditionally been viewed as controlling a transition between two distinct phenotypic phases: the bvg(+) or virulent phase and the bvg(-) or avirulent phase. recently, we identified a phenotypic phase of bordetella bronchiseptica that displays reduced virulence in a rat model of respiratory infection concomitant with increased ability to survive nutrient deprivation. characterization of this phase, designated bvg-intermediate (bvg(i)), indicat ... | 2001 | 11123689 |
| direct role of plasma membrane-expressed gp120/41 in toxicity to human astrocytes induced by hiv-1-infected macrophages. | to compare astrocyte toxicity induced by plasma membrane-expressed gp120/41 and soluble gp120. | 2000 | 11125887 |
| is leukocytosis a predictor of mortality in severe pertussis infection? | bordetella pertussis causing severe respiratory failure in infants that is unresponsive to treatment is well described. pulmonary hypertension is a prominent feature of such cases. in this series of 13 critically ill infants with b. pertussis, hyperleukocytosis ( > 100 x 10(9)/l) was an independent predictor of death. we suggest that such extreme leukocytosis may contribute to disease severity via the formation of aggregates in the pulmonary vasculature. | 2000 | 11126265 |