Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| supramolecular structure of the shigella type iii secretion machinery: the needle part is changeable in length and essential for delivery of effectors. | we investigated the supramolecular structure of the shigella: type iii secretion machinery including its major components. our results indicated that the machinery was composed of needle and basal parts with respective lengths of 45.4 +/- 3.3 and 31.6 +/- 0.3 nm, and contained mxid, mxig, mxij and mxih. spa47, encoding a putative f(1)-type atpase, was required for the secretion of effector proteins via the type iii system and was involved in the formation of the needle. the spa47 mutant produced ... | 2000 | 10921870 |
| bacterial type iv secretion: conjugation systems adapted to deliver effector molecules to host cells. | several bacterial pathogens utilize conjugation machines to export effector molecules during infection. such systems are members of the type iv or 'adapted conjugation' secretion family. the prototypical type iv system is the agrobacterium tumefaciens t-dna transfer machine, which delivers oncogenic nucleoprotein particles to plant cells. other pathogens, including bordetella pertussis, legionella pneumophila, brucellaspp. and helicobacter pylori, use type iv machines to export effector proteins ... | 2000 | 10920394 |
| differential modulation and subsequent blockade of mitogenic signaling and cell cycle progression by pasteurella multocida toxin. | the intracellularly acting protein toxin of pasteurella multocida (pmt) causes numerous effects in cells, including activation of inositol 1,4,5-trisphosphate (ip(3)) signaling, ca(2+) mobilization, protein phosphorylation, morphological changes, and dna synthesis. the direct intracellular target of pmt responsible for activation of the ip(3) pathway is the g(q/11)alpha-protein, which stimulates phospholipase c (plc) beta1. the relationship between pmt-mediated activation of the g(q/11)-plc-ip(3 ... | 2000 | 10899852 |
| effects of intranasal inoculation of porcine reproductive and respiratory syndrome virus, bordetella bronchiseptica, or a combination of both organisms in pigs. | to examine effects of co-infection with porcine reproductive and respiratory syndrome virus (prrsv) and bordetella bronchiseptica in pigs. | 2000 | 10951978 |
| role of bordetella bronchiseptica fimbriae in tracheal colonization and development of a humoral immune response. | fimbriae are filamentous, cell surface structures which have been proposed to mediate attachment of bordetella species to respiratory epithelium. bordetella bronchiseptica has four known fimbrial genes: fim2, fim3, fimx, and fima. while these genes are unlinked on the chromosome, their protein products are assembled and secreted by a single apparatus encoded by the fimbcd locus. the fimbcd locus is embedded within the fha operon, whose genes encode another putative adhesin, filamentous hemagglut ... | 2000 | 10722598 |
| effect of temperature modulation and bvg mutation of bordetella bronchiseptica on adhesion, intracellular survival and cytotoxicity for swine alveolar macrophages. | bordetella bronchiseptica causes respiratory disease in swine, yet there are no studies examining the interaction of b. bronchiseptica with swine alveolar macrophages. a swine isolate of b. bronchiseptica was able to adhere to, and survive intracellularly in, swine alveolar macrophages, but the relative ability of the bacteria to accomplish these functions was dependent on its phenotypic phase and culture conditions. more bacteria were observed extracellularly as well as intracellularly by immun ... | 2000 | 10731613 |
| phenotypic and genotypic diversity of the flagellin gene (flic) among clostridium difficile isolates from different serogroups. | phenotypic and genotypic diversity of the flagellin gene (flic) of clostridium difficile was studied in 47 isolates from various origins belonging to the serogroups a, b, c, d, f, g, h, i, k, x, and s3. electron microscopy revealed 17 nonflagellated strains and 30 flagellated strains. pcr and reverse transcription-pcr demonstrated that the flagellin gene was present in all strains and that the flic gene was expressed in both flagellated and nonflagellated strains. southern blotting showed the pr ... | 2000 | 10970353 |
| role of manganese-containing superoxide dismutase in oxidative stress and virulence of streptococcus pneumoniae. | streptococcus pneumoniae was shown to contain two types of superoxide dismutase, mnsod and fesod. levels of mnsod increased during growth in an aerobic environment. the soda gene, encoding mnsod, of virulent s. pneumoniae type 2 strain d39 was inactivated to give mutant d39hy1. aerobically, d39hy1 had a lower growth rate than the wild type and exhibited susceptibility to the redox-active compound paraquat, but anaerobic growth of d39hy1 was identical to that of the wild type. virulence studies s ... | 2000 | 10768978 |
| interaction of salmonella enterica serotype typhimurium with dendritic cells is defined by targeting to compartments lacking lysosomal membrane glycoproteins. | dendritic cells (dcs) play a central role in the generation of acquired immunity to infections by pathogenic microorganisms. salmonella enterica serotype typhimurium is known to survive and proliferate intracellularly within macrophages and nonphagocytic cells, but no data exist on how this pathogen interacts with dcs. in this report, we show the capacity of serotype typhimurium to survive within the established mouse dc line cb1. in contrast to the case for the macrophage model, the compartment ... | 2000 | 10768999 |
| detection of legionella species in respiratory specimens using pcr with sequencing confirmation. | legionella spp. are a common cause of community-acquired respiratory tract infections and an occasional cause of nosocomial pneumonia. a pcr method for the detection of legionellae in respiratory samples was evaluated and was compared to culture. the procedure can be performed in 6 to 8 h with a commercially available dna extraction kit (qiagen, valencia, calif.) and by pcr with gel detection. pcr is performed with primers previously determined to amplify a 386-bp product within the 16s rrna gen ... | 2000 | 10790085 |
| the p21 rho-activating toxin cytotoxic necrotizing factor 1 is endocytosed by a clathrin-independent mechanism and enters the cytosol by an acidic-dependent membrane translocation step. | cytotoxic necrotizing factor 1 (cnf1), a protein produced by pathogenic strains of escherichia coli, activates the p21 rho-gtp-binding protein, inducing a profound reorganization of the actin cytoskeleton. cnf1 binds to its cell surface receptor on hep-2 cells with high affinity (k(d) = 20 pm). in hep-2 cells the action of cnf1 is not blocked in the presence of filipin, a drug described to reduce cholera toxin internalization by the caveolae-like mechanism. moreover, hep-2 cells, which express a ... | 2000 | 10793151 |
| 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 |
| characterization of fimy as a coactivator of type 1 fimbrial expression in salmonella enterica serovar typhimurium. | type 1 fimbriae of salmonella enterica serovar typhimurium are surface appendages that carry adhesins specific for mannosylated host glycoconjugates. regulation of the major fimbrial subunit is thought to be controlled by a number of ancillary fim genes, including fimz, fimy, fimw, and fimu. previous studies using a fimz mutant have indicated that this protein is necessary for fima expression, and in vitro dna binding assays determined that fimz is a transcriptional activator that binds directly ... | 2000 | 10816478 |
| identification of a human lactoferrin-binding protein in gardnerella vaginalis. | previous studies have shown that gardnerella vaginalis can utilize iron-loaded human lactoferrin as a sole source of iron. in this study, g. vaginalis cells were shown to bind digoxigenin (dig)-labeled human lactoferrin in a dot blot assay. using the dig-labeled human lactoferrin, a 120-kda human lactoferrin-binding protein was detected by western blot analysis of g. vaginalis proteins. the lactoferrin-binding activity of this protein was found to be heat stable. competition studies indicated th ... | 2000 | 10816496 |
| use of pertussis toxin encoded by ptx genes from bordetella bronchiseptica to model the effects of antigenic drift of pertussis toxin on antibody neutralization. | recently, concern has been voiced about the potential effect that antigenic divergence of circulating strains of bordetella pertussis might have on the efficacy of pertussis vaccines. in order to model antigenic drift of pertussis toxin, a critical component of many pertussis vaccines, and to examine the effects of such drift on antibody neutralization, we engineered a strain of b. pertussis to produce a variant pertussis toxin molecule that contains many of the amino acid changes found in the t ... | 2000 | 10816544 |
| characterization of sepl of enterohemorrhagic escherichia coli. | the sepl gene is expressed in the locus of enterocyte effacement and therefore is most likely implicated in the attaching and effacing process, as are the products encoded by open reading frames located up- and downstream of this gene. in this study, the sepl gene of the enterohemorrhagic escherichia coli (ehec) strain edl933 was analyzed and the corresponding polypeptide was characterized. we found that sepl is transcribed monocistronically and independently from the esp operon located downstre ... | 2000 | 11053395 |
| molecular characterization of bordetella bronchiseptica filamentous haemagglutinin and its secretion machinery. | two closely related pathogens, bordetella pertussis and bordetella bronchiseptica, share a number of virulence factors. filamentous haemagglutinin (fha) is widely regarded as the dominant adhesin of b. pertussis, and its multiple binding activities have been well characterized. this large protein is produced and secreted at high levels by b. pertussis and significantly lower levels by b. bronchiseptica strains. fha secretion is mediated by a single outer-membrane accessory protein, fhac. the gen ... | 2000 | 10832649 |
| recovery of bordetella holmesii from patients with pertussis-like symptoms: use of pulsed-field gel electrophoresis to characterize circulating strains. | a 4-year retrospective study showing that we isolated bordetella holmesii, but not bordetella pertussis, from patients with pertussis-like symptoms was performed. from 1995 through 1998, we isolated b. holmesii from 32 nasopharyngeal specimens that had been submitted from patients suspected of having pertussis. previously, b. holmesii had been associated mainly with septicemia and was not thought to be associated with respiratory illness. a study was undertaken to describe the characteristics of ... | 2000 | 10834997 |
| 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 |
| 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 |
| evidence for a signaling system in helicobacter pylori: detection of a luxs-encoded autoinducer. | helicobacter pylori possesses a homolog of the luxs gene, initially identified by its role in autoinducer production for the quorum-sensing system 2 in vibrio harveyi. the genomes of several other species of bacteria, notably escherichia coli, salmonella enterica serovar typhimurium, and vibrio cholerae, also include luxs homologs. all of these bacteria have been shown to produce active autoinducers capable of stimulating the expression of the luciferase operon in v. harveyi. in this report, we ... | 2000 | 10850976 |
| genetic and environmental factors affecting t-pilin export and t-pilus biogenesis in relation to flagellation of agrobacterium tumefaciens. | the t pilus, primarily composed of cyclic t-pilin subunits, is essential for the transmission of the ti-plasmid t-dna from agrobacterium tumefaciens to plant cells. although the virb2 gene of the 11-gene virb operon was previously demonstrated to encode the full-length propilin, and other genes of this operon have been implicated as members of a conserved transmembrane transport apparatus, the role of each virb gene in t-pilin synthesis and transport and t-pilus biogenesis remained undefined. in ... | 2000 | 10850985 |
| importance of holotoxin assembly in ptl-mediated secretion of pertussis toxin from bordetella pertussis. | we examined the structural components of pertussis toxin that are required for efficient export from bordetella pertussis via the ptl system, a member of the type iv family of macromolecular transporters. first, we constructed a strain of b. pertussis that contains a functional ptl system but does not produce pertussis toxin. plasmids which express either the s1 subunit or the b oligomer were then introduced into this strain. we found that the b oligomer of the toxin is not secreted in the absen ... | 2000 | 10858221 |
| 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 |
| the structure of the carbohydrate backbone of the lipopolysaccharides from bordetella hinzii and bordetella bronchiseptica. | the structure of the core-lipid a region of the lipopolysaccharides from bordetella hinzii and bordetella bronchiseptica has been analyzed. lipopolysaccharides were deacylated using strong alkaline hydrolysis, the products were separated by high performance anion-exchange chromatography and analyzed by nmr and mass spectrometry. the following structure of the products can be deduced from the experimental results: where for the product from bordetella hinzii n = h, r = h, beta-fucn4n- or partiall ... | 2000 | 10880983 |
| fatal pneumonia due to bordetella bronchiseptica. | 2000 | 10892400 | |
| simultaneous identification of two cyclohexanone oxidation genes from an environmental brevibacterium isolate using mrna differential display. | the technique of mrna differential display was used to identify simultaneously two metabolic genes involved in the degradation of cyclohexanone in a new halotolerant brevibacterium environmental isolate. in a strategy based only on the knowledge that cyclohexanone oxidation was inducible in this strain, the mrna population of cells exposed to cyclohexanone was compared to that of control cells using reverse transcription-pcr reactions primed with a collection of 81 arbitrary oligonucleotides. th ... | 2000 | 10894733 |
| role of phosphoglucomutase of bordetella bronchiseptica in lipopolysaccharide biosynthesis and virulence. | the phosphoglucomutase (pgm)-encoding gene of bordetella bronchiseptica is required for lipopolysaccharide (lps) biosynthesis. an insertion mutant of the wild-type b. bronchiseptica strain bb7865 which disrupted lps biosynthesis was created and characterized (bb7865pgm). genetic analysis of the mutated gene showed it shares high identity with pgm genes of various bacterial species and forms part of an operon which also encompasses the gene encoding phosphoglucose isomerase. functional assays for ... | 2000 | 10899872 |
| a role for lipopolysaccharide in turkey tracheal colonization by bordetella avium as demonstrated in vivo and in vitro. | we isolated two insertion mutants of bordetella avium that exhibited a peculiar clumped-growth phenotype and found them to be attenuated in turkey tracheal colonization. the mutants contained transposon insertions in homologues of the wlba and wlbl genes of bordetella pertussis. the wlb genetic locus of b. pertussis has been previously described as containing 12 genes involved in lipopolysaccharide (lps) biosynthesis. polyacrylamide gel analysis of lps from b. avium wlba and wlbl insertion mutan ... | 2000 | 10931292 |
| disease patterns in field and bank vole populations during a cyclic decline in central finland. | declining field vole (microtus agrestis) and bank vole (clethrionomys glareolus) populations were sampled (117 field voles and 34 bank voles) in south-central finland during the winter of 1988-89. the last surviving field voles were caught in april and bank voles in february. a subsample (16) of the april field voles were taken live to the laboratory for immunosuppression. the histopathology of the main internal organs and the presence of aerobic bacteria and certain parasites were studied. in t ... | 2000 | 10670697 |
| molecular characterization of two-component systems of helicobacter pylori. | two-component systems are frequently involved in the adaptation of bacteria to changing environmental conditions at the level of transcriptional regulation. here we report the characterization of members of the two-component systems of the gastric pathogen helicobacter pylori deduced from the genome sequence of strain 26695. we demonstrate that the response regulators hp166, hp1043, and hp1021 have essential functions, as disruption of the corresponding genes is lethal for the bacteria, irrespec ... | 2000 | 10735847 |
| diagnosis and differentiation of mycoplasma hyopneumoniae and mycoplasma hyorhinis infections in pigs by pcr amplification of the p36 and p46 genes. | the genome of mycoplasma hyopneumoniae encodes several immunodominant proteins, including a cytosolic protein (p36), three membranous proteins (p46, p65, and p74), and an adhesin (p97). cross-reactions with m. flocculare and m. hyorhinis reduce the specificity of conventional serological detection methods. however, certain antigenic determinants of the p36 and p46 proteins have been shown to be specific for m. hyopneumoniae. in the present study, pairs of oligonucleotide primers were designed to ... | 2000 | 10747113 |
| evaluation of autoscan-w/a and the vitek gni+ automicrobic system for identification of non-glucose-fermenting gram-negative bacilli. | the autoscan-w/a (w/a; dade behring microscan inc., west sacramento, calif.) and vitek automicrobic system (vitek ams; biomérieux vitek systems, inc., hazelwood, mo.) are both fully automated microbiology systems. we evaluated the accuracy of these two systems in identifying nonglucose-fermenting gram-negative bacilli. we used the w/a with conventional-panel neg combo type 12 and vitek gni+ identification systems. a total of 301 isolates from 25 different species were tested. of these, 299 isola ... | 2000 | 10699007 |
| modulation of host immune responses, induction of apoptosis and inhibition of nf-kappab activation by the bordetella type iii secretion system. | bordetella bronchiseptica establishes respiratory tract infections in laboratory animals with high efficiency. colonization persists for the life of the animal and infection is usually asymptomatic in immunocompetent hosts. we hypothesize that this reflects a balance between immunostimulatory events associated with infection and immunomodulatory events mediated by the bacteria. we have identified 15 loci that are part of a type iii secretion apparatus in b. bronchiseptica and three secreted prot ... | 2000 | 10712682 |
| detection of type iii secretion system genes in animal isolates of bordetella bronchiseptica. | a cosmid clone bank of bordetella bronchiseptica genomic dna was screened for the presence of type iii secretion (tts) genes using a probe derived from the tts system genes of ralstonia solanacearum. a 3.35kb psti fragment, sub-cloned from a hybridising cosmid clone, was sequenced and found to contain a 97bp overlap with the previously reported b. bronchiseptica bscijklno tts gene cluster. dna and predicted protein homology analysis suggests that a bscpqrst cluster lies immediately downstream of ... | 2000 | 10727842 |
| antibiotic susceptibility of canine bordetella bronchiseptica isolates. | the antimicrobial sensitivities of 78 recent (1995-1998) canine isolates of bordetella bronchiseptica from 13 separate sources were determined. minimum inhibitory concentrations were assessed using the e-test method or by agar dilution. all 78 isolates were sensitive to tetracycline, doxycycline, enrofloxacin, and amoxycillin/clavulanic acid; the majority were sensitive to ampicillin (63/78; 81%), trimethoprim (57/78; 73%), and sulphadiazine (63/78; 81%). plasmids were detected in 14 out of the ... | 2000 | 10703703 |
| application of 16s rrna gene sequencing to identify bordetella hinzii as the causative agent of fatal septicemia. | we report on the first case of fatal septicemia caused by bordetella hinzii. the causative organism exhibited a biochemical profile identical to that of bordetella avium with three commercial identification systems (api 20e, api 20 ne, and vitek gni+ card). however, its cellular fatty acid profile was not typical for either b. avium or previously reported strains of b. hinzii. presumptive identification of the patient's isolate was accomplished by traditional biochemical testing, and definitive ... | 2000 | 10655386 |
| presence of type iii secretion genes in burkholderia pseudomallei correlates with ara(-) phenotypes. | dot blot hybridization and pcr amplification of 14 ara(+) and 8 ara(-) burkholderia pseudomallei strains showed that type iii secretion (tts) genes were present in all the ara(-) strains but absent from all but one of the ara(+) strains. the link between tts genes and an ara(-) phenotype suggests a role for tts in virulence. | 2000 | 10655407 |
| bordetella bronchiseptica infection in cats following contact with infected dogs. | 2000 | 10678811 | |
| prevalence of bordetella bronchiseptica in cats attended by a veterinary practice in the manawatu region. | to determine the prevalence by isolation of bordetella bronchiseptica infection in healthy cats and in cats showing signs of upper respiratory tract (urt) disease attended by a veterinary practice in the manawatu region. | 2000 | 16032125 |
| polymorphism of bordetella pertussis isolates circulating for the last 10 years in france, where a single effective whole-cell vaccine has been used for more than 30 years. | we compared bordetella pertussis isolates collected in france over the last 10 years, the vaccine strains used for more than 30 years, and isolates collected before the introduction of generalized vaccination. the analysis included serotyping, pulsed-field gel electrophoresis of chromosomal dna after digestion with xbai and spei, and sequencing of the pt s1 gene, encoding the s1 subunit of pertussis toxin, and the prn gene, encoding the adhesin pertactin. we found that the incidence of infection ... | 2001 | 11724851 |
| characterization of intermediate phenotypes induced by chemically undefined laboratory media in virulent bordetella bronchiseptica strains. | the expression of many virulence factors of bordetella bronchiseptica is regulated by the bvgas locus and reduced in response to environmental signals called modulators. virulent strains can alternate between virulent (bvg(+)), intermediate (bvg(i)), and modulated (bvg(+)mod) phenotypes. potential vaccine antigens can be expressed by bvg1 strains grown only in the absence of modulators. in the present study we evaluated filamentous hemagglutinin (fha) and outer membrane protein (omp) expression ... | 2001 | 12483567 |
| 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 |
| detection of bacterial virulence genes by subtractive hybridization: identification of capsular polysaccharide of burkholderia pseudomallei as a major virulence determinant. | burkholderia pseudomallei, the etiologic agent of melioidosis, is responsible for a broad spectrum of illnesses in humans and animals particularly in southeast asia and northern australia, where it is endemic. burkholderia thailandensis is a nonpathogenic environmental organism closely related to b. pseudomallei. subtractive hybridization was carried out between these two species to identify genes encoding virulence determinants in b. pseudomallei. screening of the subtraction library revealed a ... | 2001 | 11119486 |
| legionella pneumophila major acid phosphatase and its role in intracellular infection. | legionella pneumophila is an intracellular pathogen of protozoa and alveolar macrophages. this bacterium contains a gene (pild) that is involved in both type iv pilus biogenesis and type ii protein secretion. we previously demonstrated that the pild prepilin peptidase is crucial for intracellular infection by l. pneumophila and that the secreted pild-dependent proteins include a metalloprotease, an acid phosphatase, an esterase/lipase, a phospholipase a, and a p-nitrophenyl phosphorylcholine hyd ... | 2001 | 11119504 |
| the bordetella bhu locus is required for heme iron utilization. | bordetella pertussis and bordetella bronchiseptica are capable of obtaining iron from hemin and hemoglobin. genes encoding a putative bacterial heme iron acquisition system (bhu, for bordetella heme utilization) were identified in a b. pertussis genomic sequence database, and the corresponding dna was isolated from a virulent strain of b. pertussis. a b. pertussis bhur mutant, predicted to lack the heme outer membrane receptor, was generated by allelic exchange. in contrast to the wild-type stra ... | 2001 | 11418569 |
| a mems based amperometric detector for e. coli bacteria using self-assembled monolayers. | we developed a system for amperometric detection of escherichia coli (e. coli) based on the integration of microelectromechanical systems (mems), self-assembled monolayers (sams), dna hybridization, and enzyme amplification. using mems technology, a detector array was fabricated which has multiple electrodes deposited on a si wafer and was fully reusable. using sams, a monolayer of the protein streptavidin was immobilized on the working electrode (au) surface to capture rrna from e. coli. three ... | 2001 | 11679252 |
| [the current antimicrobial resistance situation in swiss veterinary medicine]. | antimicrobial susceptibility data (n = 1501) and bacterial isolates (n = 258) of important bacterial pathogens from animals were collected in collaboration with eight swiss laboratories from may 1999 to february 2000. using these data, the antimicrobial resistance situation could be assessed for the following bacterial species: escherichia coli, salmonella, haemophilus parasuis, actinobacillus pleuropneumoniae, pasteurella multocida, mannheimia haemolytica, bordetella bronchiseptica, campylobact ... | 2001 | 11680911 |
| expression of the putative siderophore receptor gene bfrz is controlled by the extracytoplasmic-function sigma factor bupi in bordetella bronchiseptica. | a new gene from bordetella bronchiseptica, bfrz encoding a putative siderophore receptor, was identified in a fur-repressor titration assay. a bfrz null mutant was constructed by allelic exchange. the protein profile of this mutant is similar to that of the wild-type parent strain. the bfrz(-)-bfrz(+) isogenic pair was tested for utilization of 132 different siderophores as iron sources. none of these iron sources acted as a ligand for bfrz. translational bfrz::phoa and transcriptional bfrz::lac ... | 2001 | 11292812 |
| isolation and characterization of four bactericidal domains in the bovine beta-lactoglobulin. | proteolytic digestion of bovine beta-lactoglobulin by trypsin yielded four peptide fragments with bactericidal activity. the peptides were isolated and their sequences were found as follows: vagtwy (residues 15-20), aasdislldaqsaplr (residues 25-40), ipavfk (residues 78-83) and vlvldtdyk (residues 92-100). the four peptides were synthesized and found to exert bactericidal effects against the gram-positive bacteria only. in order to understand the structural requirements for antibacterial activit ... | 2001 | 11325534 |
| novel genetic and phenotypic heterogeneity in bordetella bronchiseptica pertactin. | the bordetella bronchiseptica outer membrane protein pertactin is believed to function as an adhesin and is an important protective immunogen. previous sequence analysis of the pertactin gene identified two regions predicted to encode amino acid repeat motifs. recent studies have documented dna sequence heterogeneity in both regions. the present study describes additional variants in these regions, which form the basis for six novel pertactin types. immunoblotting demonstrated phenotypic heterog ... | 2001 | 11179374 |
| sira orthologs affect both motility and virulence. | the sira gene of salmonella enterica serovar typhimurium encodes a two-component response regulator of the fixj family that has a positive regulatory influence on the expression of type iii secretion genes involved with epithelial cell invasion and the elicitation of bovine gastroenteritis. sira orthologs in pseudomonas, vibrio, and erwinia control the expression of distinct virulence genes in these genera, but an evolutionarily conserved target of sira regulation has never been identified. in t ... | 2001 | 11244064 |
| epitope mapping of monoclonal antibodies capable of neutralizing cytotoxic necrotizing factor type 1 of uropathogenic escherichia coli. | cytotoxic necrotizing factor type 1 (cnf1) of uropathogenic escherichia coli belongs to a family of bacterial toxins that target the small gtp-binding rho proteins that regulate the actin cytoskeleton. members of this toxin family typically inactivate rho; however, cnf1 and the highly related cnf2 activate rho by deamidation. other investigators have reported that the first 190 amino acids of cnf1 constitute the cellular binding domain and that the cnf1 enzymatic domain lies within a 300-amino-a ... | 2001 | 11254559 |
| reduced virulence of a bordetella bronchiseptica siderophore mutant in neonatal swine. | one means by which bordetella bronchiseptica scavenges iron is through production of the siderophore alcaligin. a nonrevertible alcaligin mutant derived from the virulent strain 4609, designated dbb25, was constructed by insertion of a kanamycin resistance gene into alca, one of the genes essential for alcaligin biosynthesis. the virulence of the alca mutant in colostrum-deprived, caesarean-delivered piglets was compared with that of the parent strain in two experiments. at 1 week of age, piglet ... | 2001 | 11254568 |
| pseudomonas stutzeri has two closely related pila genes (type iv pilus structural protein) with opposite influences on natural genetic transformation. | pseudomonas stutzeri has type iv pili for which the pila gene (here termed pilai) provides the structural protein and which are required for dna uptake and natural genetic transformation. downstream of pilai we identified a gene, termed pilaii, coding for a deduced protein with a size similar to that of pilai with 55% amino acid sequence identity and with a typical leader peptide including a leader peptidase cleavage site. fusions to lacz revealed that pilaii is expressed only about 10% compared ... | 2001 | 11244078 |
| construction of mini-tn5cyaa' and its utilization for the identification of genes encoding surface-exposed and secreted proteins in bordetella bronchiseptica. | a mini-tn5 transposon derivative, mini-tn5cyaa', has been constructed. it contains a promoter-less and ribosome binding site-deficient reporter gene, encoding the catalytic domain of bordetella pertussis adenylate cyclase toxin (cyaa'). we used this system to mutagenize b. bronchiseptica and we developed a screen for identification of mutants containing cyaa' translational fusions. this system was used to identify b. bronchiseptica genes that encode surface-exposed and secreted proteins. | 2001 | 11728725 |
| proinflammatory and proapoptotic activities associated with bordetella pertussis filamentous hemagglutinin. | filamentous hemagglutinin (fha) is a dominant cell surface-associated bordetella pertussis adhesin. recognition that this protein is secreted in significant amounts and that bacterial adhesins may have other activities, prompted an assessment of fha effects on human macrophages. incubation of human macrophage-like u937 cells with preparations of fha resulted in dose-dependent cytotoxicity, with death of 95% of treated cells after 24 h. based on the use of four independent methods, death of these ... | 2001 | 11254631 |
| polysaccharide biosynthesis locus required for virulence of bacteroides fragilis. | bacteroides fragilis, though only a minor component of the human intestinal commensal flora, is the anaerobe most frequently isolated from intra-abdominal abscesses. b. fragilis 9343 expresses at least three capsular polysaccharides-polysaccharide a (ps a), ps b, and ps c. purified ps a and ps b have been tested in animal models and are both able to induce the formation of intra-abdominal abscesses. mutants unable to synthesize ps b or ps c still facilitate abscess formation at levels comparable ... | 2001 | 11401972 |
| role played by the response regulator ris in bordetella bronchiseptica resistance to macrophage killing. | previous studies suggested that the persistence in eukaryotic cells of a bordetella bronchiseptica mutant carrying an insertion in the locus encoding the response regulator risas is impaired. this suggested that ris-dependent products are required for the intracellular survival of bacteria. in this study we demonstrate that ris-regulated products play a role in b. bronchiseptica resistance against both phagosomal acidification and reactive oxygen intermediates. | 2001 | 11470358 |
| variation in bordetella bronchiseptica flaa does not correlate with typing by macro-restriction analysis by pulsed-field gel electrophoresis. | a genotyping method based on pcr-rflp analysis of the flagellin gene (flaa) was applied to 30 mainly feline isolates of bordetella bronchiseptica. these isolates were separated into three pcr-rflp groups with the restriction endonucleases haeiii, mspi, mboi and rsai. flaa nucleotide sequences representing each of the three groups differed from each other by 11-13%. one of the groups exhibited far greater flaa sequence identity with the cryptic flagellin gene sequence of b. pertussis (>97%) than ... | 2001 | 11232772 |
| globin-coupled sensors: a class of heme-containing sensors in archaea and bacteria. | the recently discovered prokaryotic signal transducer hemat, which has been described in both archaea and bacteria, mediates aerotactic responses. the n-terminal regions of hemat from the archaeon halobacterium salinarum (hemat-hs) and from the gram-positive bacterium bacillus subtilis (hemat-bs) contain a myoglobin-like motif, display characteristic heme-protein absorption spectra, and bind oxygen reversibly. recombinant hemat-hs and hemat-bs shorter than 195 and 176 residues, respectively, do ... | 2001 | 11481493 |
| demonstration of polysaccharide capsule in campylobacter jejuni using electron microscopy. | recently, we reported that campylobacter jejuni, an important gastrointestinal pathogen, has the genetic determinants to produce a capsular polysaccharide (karlyshev et al., mol. microbiol. 35:529-541, 2000). despite these data, the presence of a capsule in these bacteria has remained controversial. in this study we stain c. jejuni cells with the cationic dye alcian blue and demonstrate for the first time by electron microscopy that c. jejuni cells produce a polysaccharide capsule that is retain ... | 2001 | 11500474 |
| escherichia coli cytotoxic necrotizing factor and pasteurella multocida toxin induce focal adhesion kinase autophosphorylation and src association. | cytotoxic necrotizing factor 1 and pasteurella multocida toxin induced dose- and time-dependent increases in focal adhesion kinase (fak) tyr397 phosphorylation in swiss 3t3 cells. fak autophosphorylation was sensitive to inhibitors of p160/rock and coincided with the formation of stable complexes between fak and src family members. | 2001 | 11500476 |
| mobilization function of the pbhr1 plasmid, a derivative of the broad-host-range plasmid pbbr1. | the pbhr1 plasmid is a derivative of the small (2.6-kb), mobilizable broad-host-range plasmid pbbr1, which was isolated from the gram-negative bacterium bordetella bronchiseptica (r. antoine and c. locht, mol. microbiol. 6:1785-1799, 1992). plasmid pbbr1 consists of two functional cassettes and presents sequence similarities with the transfer origins of several plasmids and mobilizable transposons from gram-positive bacteria. we show that the mob protein specifically recognizes a 52-bp sequence ... | 2001 | 11222611 |
| a case-control study of respiratory disease in thoroughbred racehorses in sydney, australia. | in order to investigate the role of infectious agents in the aetiology of lower respiratory tract disease in thoroughbred racehorses, a matched case-control study was conducted. cases were identified by the presence of coughing, and were compared to a control population matched on time of sample collection and location within the same training establishment. tracheal wash samples were collected from 100 cases and 148 controls. case horses were more likely than controls to have endoscopic and cyt ... | 2001 | 11352347 |
| diversity in the bordetella virulence regulon: transcriptional control of a bvg-intermediate phase gene. | the bvgas signal transduction system controls the expression of at least three distinct phenotypic phases that lie along a continuum of gene expression states. the bvg+ phase is characterized by the expression of adhesins and toxins, whereas the bvg- phase is characterized by motility in bordetella bronchiseptica and the expression of vrg loci in bordetella pertussis. the bvg-intermediate (bvgi) phase is characterized by the absence of bvg-repressed phenotypes, the expression of some, but not al ... | 2001 | 11359572 |
| 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 |
| complete nucleotide sequence of a 43-kilobase genomic island associated with the multidrug resistance region of salmonella enterica serovar typhimurium dt104 and its identification in phage type dt120 and serovar agona. | this study describes the characterization of the recently described salmonella genomic island 1 (sgi1) (d. a. boyd, g. a. peters, l.-k. ng, and m. r. mulvey, fems microbiol. lett. 189:285-291, 2000), which harbors the genes associated with the acssut phenotype in a canadian isolate of salmonella enterica serovar typhimurium dt104. a 43-kb region has been completely sequenced and found to contain 44 predicted open reading frames (orfs) which comprised approximately 87% of the total sequence. fift ... | 2001 | 11544236 |
| role of adp-ribosyltransferase activity of pertussis toxin in toxin-adhesin redundancy with filamentous hemagglutinin during bordetella pertussis infection. | pertussis toxin (pt) and filamentous hemagglutinin (fha) are two major virulence factors of bordetella pertussis. fha is the main adhesin, whereas pt is a toxin with an a-b structure, in which the a protomer expresses adp-ribosyltransferase activity and the b moiety is responsible for binding to the target cells. here, we show redundancy of fha and pt during infection. whereas pt-deficient and fha-deficient mutants colonized the mouse respiratory tract nearly as efficiently as did the isogenic p ... | 2001 | 11553541 |
| genetic organization of the region encoding regulation, biosynthesis, and transport of rhizobactin 1021, a siderophore produced by sinorhizobium meliloti. | eight genes have been identified that function in the regulation, biosynthesis, and transport of rhizobactin 1021, a hydroxamate siderophore produced under iron stress by sinorhizobium meliloti. the genes were sequenced, and transposon insertion mutants were constructed for phenotypic analysis. six of the genes, named rhbabcdef, function in the biosynthesis of the siderophore and were shown to constitute an operon that is repressed under iron-replete conditions. another gene in the cluster, name ... | 2001 | 11274118 |
| gonococcal genes encoding transferrin-binding proteins a and b are arranged in a bicistronic operon but are subject to differential expression. | neisseria gonorrhoeae is capable of utilizing host iron-binding proteins, such as transferrin, lactoferrin, and hemoglobin, as the sole source of iron. the receptor involved in transferrin iron acquisition is composed of two distinct transferrin-binding proteins, tbpa and tbpb. the genes that encode these proteins are linked on the chromosome in the order tbpb-tbpa but are separated by an inverted repeat of unknown function. in this study, we sought to understand the transcriptional organization ... | 2001 | 11553578 |
| differential regulation of bvg-activated virulence factors plays a role in bordetella pertussis pathogenicity. | bordetella pertussis, the causative agent of whooping cough, regulates expression of many virulence factors via a two-component signal transduction system encoded by the bvgas regulatory locus. it has been shown by transcription activation kinetics that several of the virulence factors are differentially regulated. fha is transcribed within 10 min following a bvgas-inducing signal, while prn is transcribed after 1 h and ptx is not transcribed until 2 to 4 h after induction. these genes therefore ... | 2001 | 11254549 |
| comparison of nucleic acid amplification, serology, and microbiologic culture for diagnosis of rhodococcus equi pneumonia in foals. | recently, a technique was described for amplification of rhodococcus equi-specific chromosomal and vapa dna from blood and tracheal wash fluids. it was hypothesized that this technique would be more sensitive than standard culture techniques or serology for diagnosis of r. equi pneumonia in foals. tracheal wash fluid, nasal swabs, whole blood samples, and serum samples from 56 foals with pneumonia were analyzed. final clinical diagnosis was determined by the attending clinician on the basis of f ... | 2001 | 11283043 |
| the esat-6 gene cluster of mycobacterium tuberculosis and other high g+c gram-positive bacteria. | the genome of mycobacterium tuberculosis h37rv has five copies of a cluster of genes known as the esat-6 loci. these clusters contain members of the cfp-10 (lhp) and esat-6 (esat-6) gene families (encoding secreted t-cell antigens that lack detectable secretion signals) as well as genes encoding secreted, cell-wall-associated subtilisin-like serine proteases, putative abc transporters, atp-binding proteins and other membrane-associated proteins. these membrane-associated and energy-providing pro ... | 2001 | 11597336 |
| brucella abortus cyclic beta-1,2-glucan mutants have reduced virulence in mice and are defective in intracellular replication in hela cells. | null cyclic beta-1,2-glucan synthetase mutants (cgs mutants) were obtained from brucella abortus virulent strain 2308 and from b. abortus attenuated vaccinal strain s19. both mutants show greater sensitivity to surfactants like deoxycholic acid, sodium dodecyl sulfate, and zwittergent than the parental strains, suggesting cell surface alterations. although not to the same extent, both mutants display reduced virulence in mice and defective intracellular multiplication in hela cells. the b. abort ... | 2001 | 11401996 |
| [bordetella bronchiseptica infection in a senegalese hiv positive patient: carrier state or illness?]. | 2001 | 11413848 | |
| clonal associations among staphylococcus aureus isolates from various sites of infection. | a molecular epidemiological analysis was undertaken to identify lineages of staphylococcus aureus that may be disproportionately associated with infection. pulsed-field gel electrophoresis analysis of 405 s. aureus clinical isolates collected from various infection types and geographic locations was performed. five distinct s. aureus lineages (sals 1, 2, 4, 5, and 6) were identified, which accounted for 19.01, 9.14, 22.72, 10.12, and 4.69% of isolates, respectively. in addition, 85 lineages whic ... | 2001 | 11119523 |
| effects of intranasal inoculation with bordetella bronchiseptica, porcine reproductive and respiratory syndrome virus, or a combination of both organisms on subsequent infection with pasteurella multocida in pigs. | to determine effects of intranasal inoculation with porcine reproductive and respiratory syndrome virus (prrsv) or bordetella bronchiseptica on challenge with nontoxigenic pasteurella multocida in pigs. | 2001 | 11327458 |
| the adenylate cyclase toxin of bordetella pertussis binds to target cells via the alpha(m)beta(2) integrin (cd11b/cd18). | the adenylate cyclase toxin (cyaa) of bordetella pertussis is a major virulence factor required for the early phases of lung colonization. it can invade eukaryotic cells where, upon activation by endogenous calmodulin, it catalyzes the formation of unregulated camp levels. cyaa intoxication leads to evident toxic effects on macrophages and neutrophils. here, we demonstrate that cyaa uses the alpha(m)beta(2) integrin (cd11b/cd18) as a cell receptor. indeed, the saturable binding of cyaa to the su ... | 2001 | 11342588 |
| identification and functional characterization of arylamine n-acetyltransferases in eubacteria: evidence for highly selective acetylation of 5-aminosalicylic acid. | arylamine n-acetyltransferase activity has been described in various bacterial species. bacterial n-acetyltransferases, including those from bacteria of the gut flora, may be involved in the metabolism of xenobiotics, thereby exerting physiopathological effects. we characterized these enzymes further by steady-state kinetics, time-dependent inhibition, and dna hybridization in 40 species, mostly from the human intestinal microflora. we report for the first time n-acetyltransferase activity in 11 ... | 2001 | 11344150 |
| actinobacillus pleuropneumoniae iron transport and urease activity: effects on bacterial virulence and host immune response. | actinobacillus pleuropneumoniae, a porcine respiratory tract pathogen, has been shown to express transferrin-binding proteins and urease during infection. both activities have been associated with virulence; however, their functional role for infection has not yet been elucidated. we used two isogenic a. pleuropneumoniae single mutants (deltaexbb and deltaurec) and a newly constructed a. pleuropneumoniae double (deltaurec deltaexbb) mutant in aerosol infection experiments. neither the a. pleurop ... | 2001 | 11119539 |
| activity and postantibiotic effect of marbofloxacin, enrofloxacin, difloxacin and ciprofloxacin against feline bordetella bronchiseptica isolates. | the minimum inhibitory concentration (mic) and postantibiotic effect (pae) of marbofloxacin, enrofloxacin, difloxacin and ciprofloxacin were evaluated in vitro against 43 feline-source bordetella bronchiseptica strains. all strains tested were susceptible to marbofloxacin and enrofloxacin (mic90 0.5mg/l), while 93 and 84% of the strains were susceptible, respectively, to ciprofloxacin and difloxacin with mic(90) values of, respectively, 1 and 8mg/l. the pae was studied in 10 strains by exposure ... | 2001 | 11356321 |
| the crystal structure of the ttcsaa protein: an export-related chaperone from thermus thermophilus. | the csaa protein was first characterized in bacillus subtilis as a molecular chaperone with export-related activities. here we report the 2.0 angstrom-resolution crystal structure of the thermus thermophilus csaa protein, designated ttcsaa. atomic structure and experiments in solution revealed a homodimer as the functional unit. the structure of the ttcsaa monomer is reminiscent of the well known oligonucleotide-binding fold, with the addition of extensions at the n- and c-termini that form an e ... | 2001 | 11157762 |
| the insect endosymbiont sodalis glossinidius utilizes a type iii secretion system for cell invasion. | sodalis glossinidius is a maternally transmitted secondary endosymbiont residing intracellularly in tissues of the tsetse flies, glossina spp. in this study, we have used tn5 mutagenesis and a negative selection procedure to derive a s. glossinidius mutant that is incapable of invading insect cells in vitro and is aposymbiotic when microinjected into tsetse. this mutant strain harbors tn5 integrated into a chromosomal gene sharing high sequence identity with a type iii secretion system invasion ... | 2001 | 11172045 |
| relatedness of streptococcus suis isolates of various serotypes and clinical backgrounds as evaluated by macrorestriction analysis and expression of potential virulence traits. | we evaluated the genetic diversity of streptococcus suis isolates of different serotypes by macrorestriction analysis and elucidated possible relationships between the genetic background, expression of potential virulence traits, and source of isolation. virulence traits included expression of serotype-specific polysaccharides, muramidase-released protein (mrp), extracellular protein factor (ef), hemolysin activity, and adherence to epithelial cells. macrorestriction analysis of streptococcal dn ... | 2001 | 11158088 |
| reciprocal protective immunity against bordetella pertussis and bordetella parapertussis in a murine model of respiratory infection. | the protective immunity induced by infection with bordetella pertussis and with bordetella parapertussis was examined in a murine model of respiratory infection. convalescent mice that had been infected by aerosol with b. pertussis or with b. parapertussis exhibited a protective immune response against b. pertussis and also against b. parapertussis. anti-filamentous hemagglutinin (anti-fha) serum immunoglobulin g (igg) and anti-fha lung iga antibodies were detected in both mice infected with b. ... | 2001 | 11598073 |
| pertussis toxin and lipopolysaccharide influence phagocytosis of bordetella pertussis by human monocytes. | the potential of human monocytes to mediate the clearance of bordetella pertussis infection was examined. bacteria expressing green fluorescent protein were incubated with adherent peripheral blood monocytes, and phagocytosis was quantified by using fluorescence microscopy. monocytes internalized only a small percentage of the adherent bacteria. surface-associated bvg-regulated virulence factors, including adenylate cyclase toxin and filamentous hemagglutinin, did not affect attachment or phagoc ... | 2001 | 11705943 |
| heme utilization in bordetella avium is regulated by rhui, a heme-responsive extracytoplasmic function sigma factor. | efficient utilization of heme as an iron (fe) source by bordetella avium requires bhur, an fe-regulated gene which encodes an outer membrane heme receptor. upstream of bhur is a 507-bp open reading frame, hereby designated rhui (for regulator of heme uptake), which codes for a 19-kda polypeptide. whereas the 19-kda polypeptide had homology to a subfamily of alternative sigma factors known as the extracytoplasmic function (ecf) sigma factors, it was hypothesized that rhui encoded a potential in-t ... | 2001 | 11598070 |
| lysine and polyamines are substrates for transglutamination of rho by the bordetella dermonecrotic toxin. | bordetella dermonecrotic toxin (dnt) catalyzes the transglutamination of glutamine-63/61 of rho gtpases, thereby constitutively activating rho proteins. here we identified second substrates for transglutamination of rhoa by dnt. the enzymatically active fragment of dnt (residues 1136 to 1451, deltadnt) induced the incorporation of l-[(14)c]lysine in rhoa in a concentration-dependent manner. also, rac and cdc42, but not ras, were transglutaminated with lysine by deltadnt. transglutamination of th ... | 2001 | 11705946 |
| case of catheter sepsis with ralstonia gilardii in a child with acute lymphoblastic leukemia. | acute lymphoblastic leukemia was diagnosed in a 7-year-old girl. two months after insertion of a central venous catheter, she developed fever and complained of headache and abdominal pain. physical examination revealed no focus of infection. a gram-negative nonfermenting bacillus was recurrently cultured from blood. extensive biochemical testing and 16s ribosomal dna sequencing led to the identification of ralstonia gilardii. | 2001 | 11724891 |
| laribacter hongkongensis gen. nov., sp. nov., a novel gram-negative bacterium isolated from a cirrhotic patient with bacteremia and empyema. | a bacterium was isolated from the blood and empyema of a cirrhotic patient. the cells were facultatively anaerobic, nonsporulating, gram-negative, seagull shaped or spiral rods. the bacterium grows on sheep blood agar as nonhemolytic, gray colonies 1 mm in diameter after 24 h of incubation at 37 degrees c in ambient air. growth also occurs on macconkey agar and at 25 and 42 degrees c but not at 4, 44, and 50 degrees c. the bacterium can grow in 1 or 2% but not 3, 4, or 5% nacl. no enhancement of ... | 2001 | 11724825 |
| betawrap: successful prediction of parallel beta -helices from primary sequence reveals an association with many microbial pathogens. | the amino acid sequence rules that specify beta-sheet structure in proteins remain obscure. a subclass of beta-sheet proteins, parallel beta-helices, represent a processive folding of the chain into an elongated topologically simpler fold than globular beta-sheets. in this paper, we present a computational approach that predicts the right-handed parallel beta-helix supersecondary structural motif in primary amino acid sequences by using beta-strand interactions learned from non-beta-helix struct ... | 2001 | 11752429 |
| cytotoxic necrotizing factor from escherichia coli induces rhoa-dependent expression of the cyclooxygenase-2 gene. | cytotoxic necrotizing factor 1 (cnf) is a toxin produced by some isolates of escherichia coli that cause extraintestinal infections. cnf can initiate signaling pathways that are mediated by the rho family of small gtpases through a covalent modification that results in constitutive activation. in addition to regulating the assembly of actin stress fibers and focal adhesion complexes, rhoa can also regulate gene expression at the level of transcription. here we demonstrate for the first time, by ... | 2001 | 11598057 |
| molecular characterization of chromosomal class c beta-lactamase and its regulatory gene in ochrobactrum anthropi. | ochrobactrum anthropi, formerly known as cdc group vd, is an oxidase-producing, gram-negative, obligately aerobic, non-lactose-fermenting bacillus of low virulence that occasionally causes human infections. it is highly resistant to all beta-lactams except imipenem. a clinical isolate, slo74, and six reference strains were tested. mics of penicillins, aztreonam, and most cephalosporins tested, including cefotaxime and ceftazidime, were >128 microg/ml and of cefepime were 64 to >128 microg/ml. cl ... | 2001 | 11451692 |
| in vitro activities of abt-773, a new ketolide, against aerobic and anaerobic pathogens isolated from antral sinus puncture specimens from patients with sinusitis. | the comparative in vitro activities of abt-773 against 207 aerobic and 162 anaerobic antral sinus puncture isolates showed that erythromycin-resistant pneumococcal strains were susceptible to abt-773 (< or =0.125 microg/ml); the mic at which 90% of the isolates tested were inhibited for haemophilus influenzae and other haemophilus spp. was 4 microg/ml; and all moraxella spp. and beta-lactamase-producing prevotella species strains were inhibited by < or =0.125 microg/ml. among the anaerobes teste ... | 2001 | 11451698 |
| activation of rho gtpases by cytotoxic necrotizing factor 1 induces macropinocytosis and scavenging activity in epithelial cells. | macropinocytosis, a ruffling-driven process that allows the capture of large material, is an essential aspect of normal cell function. it can be either constitutive, as in professional phagocytes where it ends with the digestion of captured material, or induced, as in epithelial cells stimulated by growth factors. in this case, the internalized material recycles back to the cell surface. we herein show that activation of rho gtpases by a bacterial protein toxin, the escherichia coli cytotoxic ne ... | 2001 | 11452003 |
| xenorhabdus nematophilus as a model for host-bacterium interactions: rpos is necessary for mutualism with nematodes. | xenorhabdus nematophilus, a gram-negative bacterium, is a mutualist of steinernema carpocapsae nematodes and a pathogen of larval-stage insects. we use this organism as a model of host-microbe interactions to identify the functions bacteria require for mutualism, pathogenesis, or both. in many gram-negative bacteria, the transcription factor sigma(s) controls regulons that can mediate stress resistance, survival, or host interactions. therefore, we examined the role of sigma(s) in the ability of ... | 2001 | 11466270 |
| development of a genetic system for geobacter sulfurreducens. | members of the genus geobacter are the dominant metal-reducing microorganisms in a variety of anaerobic subsurface environments and have been shown to be involved in the bioremediation of both organic and metal contaminants. to facilitate the study of the physiology of these organisms, a genetic system was developed for geobacter sulfurreducens. the antibiotic sensitivity of this organism was characterized, and optimal conditions for plating it at high efficiency were established. a protocol for ... | 2001 | 11425739 |
| development of conventional and real-time pcr assays for detection of legionella dna in respiratory specimens. | the development and validation of a pcr assay based on the use of new 16s ribosomal dna (rdna)-targeted primers to detect legionella dna in respiratory specimens are described. the assay was originally developed as conventional pcr followed by electrophoretic detection and was then adapted to lightcycler format with sybr green i detection and melting curve analysis. the 73 legionella pneumophila strains tested were amplified with both applications. in addition, 21 and 23 out of 27 other legionel ... | 2001 | 11474011 |
| experimental infection of conventional pigs with streptococcus suis serotype 2 by aerosolic exposure. | 2001 | 11503376 |