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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 66 (1990), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Bordetella pertussis strains contain at least three distinct genes coding for fimbrial subunits, designated fim2, fim3, and fimX. The sequences of the fim2 and fimX genes have been published. Here we present the sequence of the fim3 gene. Proximal and distal to the fim3 gene, regions were observed that could function as rho-independent terminators, suggesting that the gene is not part of a larger operon. Comparison of the putative promoter regions of the fim2 and fim3 genes revealed a conserved region containing a stretch of approximately 13 C's. This region may be involved in fimbrial phase variation. A comparison of the deduced amino acid sequences of the three fimbrial subunits revealed conserved, variable, and hypervariable regions. The hypervariable regions coincided with predicted antigenic determinants. Peptides derived from the conserved regions may be incorporated into a future pertussis vaccine to induced antibodies which confer protection against strains producing different fimbrial serotypes.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 13 (1982), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 12 (1981), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: We report the purification of a minor Bordetella pertussis fimbrial subunit, designated FimD, and the identification of its gene (fimD.) FimD could be purified from the bulk of major fimbrial subunits by exploiting the fact that major subunit-subunit interactions are more stable in the presence of SDS than minor-major subunit interactions. To locate the gene for FimD, internal peptides of FimD were generated, purified and sequenced. Subsequently, an oligonucleotide probe, based on the primary sequence of one peptide, was used to clone fimD. The primary structure of FimD, derived from the DNA sequence of its gene, showed homology with a number of fimbrial adhesins. Most pronounced homology was observed with MrkD, a fimbrial adhesin derived from Klebsieila pneumoniae. These observations suggest that FimD may represent a B. pertussis fimbrial adhesin. With a fimD-specific probe we detected the presence of a fimD homologue in Bordetella parapertussis and Bordetella bron-chiseptica but not in Bordetella avium. Cloning and sequencing revealed that the B. parapertussis and B. bronchiseptica fimD product differed from the B. pertussis fimD product in 20 and 1 amino acid residues, respectively. Since B. bronchiseptica is normally not a human pathogen, but causes respiratory disease in a wide range of non-human mammalian species, this may suggest that FimD recognizes a receptor that is well conserved in mammalian species. An in-frame deletion in fimD completely abolished FimD expression and also affected the expression of the major subunits Fim2 and Fim3 suggesting that, in contrast to other adhesins that are minor components of fimbriae, FimD is required for formation of the fimbrial structure.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The dramatic rise in BRO-producing M. catarrhalis strains observed in the last decades is without precedence. The aim of this study was to elucidate the events that led to the emergence of BRO-1 and BRO-2 β-lactamases. Previously, we showed bro1 and bro2 to be 〉99% identical. Data presented here suggested that bro2 was acquired by a fortuitous event and inserted between M. catarrhalis genes orf1 and orf3. Subsequently, bro1 evolved from bro2. Promoter-up mutations increased fitness of bro2, explaining its present predominance. The highly conserved nature of bro compared with orf1 and orf3 suggested that acquisition has occurred relatively recently. The random distribution of bro among M. catarrhalis fingerprint types indicated that bro has spread by horizontal transfer. Sequence analysis revealed that 80–200 bp is generally cotransferred with bro, serving as regions of homology that target bro to the same chromosomal locus. A region of 160 bases upstream of bro1 lacked polymorphism, indicating it was derived from the original strain that acquired bro2. We observed that bro was readily transferred by transformation between M. catarrhalis strains in vitro, suggesting a mechanism by which bro has disseminated. In conclusion, we have been able to reconstruct the steps that led to the emergence of BRO-producing M. catarrhalis.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The psychrotrophic bacterium Yersinia enterocolitica is characterized by temperature-dependent adaptations. To investigate Y. enterocolitica genes involved in cold adaptation, a mutant restricted in its ability to grow at 5°C was isolated from a transposon mutant library. The transposon insertion site in this psychrotrophy-defective (PD) mutant mapped 16 bp upstream of an open reading frame whose predicted amino acid sequence showed 93% similarity with the Escherichia coli exoribonuclease polynucleotide phosphorylase (PNPase), encoded by pnp. Expression of this gene was blocked in the PD mutant. However, the introduction of a second copy of pnp, including 0.33 kbp sequences upstream of its coding region, into the chromosome of the PD mutant restored pnp expression as well as the ability to grow at 5°C. Furthermore, the expression of pnp appeared to be temperature dependent: in the parental Y. enterocolitica strain, the levels of both pnp mRNA and PNPase were 1.6-fold higher at 5°C compared with 30°C. A similarly enhanced level of PNPase at 5°C was observed in the merodiploid recombinant strain, which indicates that the 0.33 kbp region upstream of pnp harboured a cold-inducible promoter. A putative cold shock promoter motif (ATTGG) was observed in this region.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS immunology and medical microbiology 26 (1999), S. 0 
    ISSN: 1574-695X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Bordetella pertussis can attach, invade and survive intracellularly in human macrophages in vitro. To study the significance of this bacterial feature in vivo, we analyzed the presence of viable bacteria in broncho-alveolar lavage (BAL) cells of mice infected with B. pertussis. We found B. pertussis to be present in a viable state in BAL fluid cells until at least 19 days after infection, suggesting B. pertussis to be able to survive in those cells. This intracellular niche may play an important role in the pathogenesis of pertussis. Pertussis toxin and the RGD sequence of the virulence factor filamentous hemagglutinin (FHA) both play a role in the attachment of B. pertussis to human and mouse macrophages in vitro and we hypothesized these virulence factors to be required for invasion and subsequent intracellular survival of B. pertussis in macrophages in vivo. A B. pertussis double mutant, in which the FHA RGD motif was changed to RAD and the ptx genes were deleted, was also found in a viable state in BAL fluid cells, albeit at lower levels than the wild-type strain. In our model, uptake of B. pertussis by alveolar phagocytes in vivo is thus, at least in part, determined by the bacterial virulence factors FHA and pertussis toxin.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: In 1992 a new Vibrio cholerae strain, designated V. cholerae O139 Bengal, emerged which has been responsible for large outbreaks of cholera in India and Bangladesh. Previously, we have shown that this strain arose from a V. cholerae O1 strain by the acquisition of novel DNA. Sequence analysis revealed that the novel DNA is flanked by two genes, rfaD and rfbQRS, which are also found in O1 strains. The mosaic structure of rfaDvco139 indicated that it was one of the regions involved in recombination between donor and acceptor DNA. However, sequence divergence between the O1 and O139 rfbQRS genes indicated that the second recombination site between donor and O1-acceptor DNA is probably located downstream of rfbDvco139. The DNA region between rfaDvco139 and rfbQRSvco139, designated otn, contained seven open reading frames (ORFs). Two ORFs, otnA and otnB, showed homology with genes involved in cell-wall polysaccharide synthesis. Mutations in otnA and otnB indicated that they are required for capsule synthesis but not lipopolysaccharide synthesis. The otn DNA is also found inV. cholerae O69 and O141 strains, and the organization of this DNA was essentially identical to that in the O139 strain. However, sequence divergence of the otnAB genes indicated that the O139 otn DNA region was not derived from the O69 or O141 strains. No antigenic relationship was found between the different V. cholerae serotypes carrying otn DNA, so the genes determining the antigenic specificity of the O antigen or capsule must be located outside the otn DNA. The O139 otn DNA contained a JUMPstart sequence, which is associated with polysaccharide-synthetic genes in several bacterial species. Furthermore, a repeat motif was observed in extragenic regions. A number of observations suggest that these sequences may facilitate gene flow between V. cholerae strains and the assembly of clusters of functionally related genes.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The biosynthesis of fimbriae is a complex process requiring multiple genes which are generally found clustered on the chromosome. In Bordetella pertussis, only major fimbrial subunit genes have been identified, and no evidence has yet been found that they are located in a fimbrial gene cluster. To locate additional genes involved in the biosynthesis of B. pertussis fimbriae, we used TnphoA mutagenesis. A PhoA+ mutant (designated B176) was isolated which was affected in the production of both serotype 2 and 3 fimbriae. Cloning and sequencing of the DNA region harbouring the transposon insertion revealed the presence of at least three additional fimbrial genes, designated fimB, fimC and fimD. The transposon was found to be located In fimD. Analysis of PhoA activity indicated that the fimbrial gene cluster was positively regulated by the bvg locus. A potential binding site for BvgA was observed upstream of fimB. FimB showed homology with the so-called chaperone-like fimbrial proteins, while FimC was homologous with a class of fimbrial proteins located in the outer membrane and presumed to be involved in transport and anchorage of fimbrial subunits. An insertion mutation in fimB abolished the expression of fimbrial subunits, implicating this gene in the biosynthesis of both serotype 2 and 3 fimbriae. Upstream of fimB a pseudogene (fimA) was observed which showed homology with the three major fimbrial subunit genes, fim2, fim3 and fimX. The construction of a phylogenetic tree suggested that fimA may be the primordial major fimbrial subunit gene from which the other three were derived by gene duplication. Interestingly, the fimbrial gene cluster was found to be located directly downstream from the gene coding for the filamentous haemagglutinin, an important B. pertussis adhesin, possibly suggesting co-operation between the two loci in the pathogenesis of pertussis.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The chromosome of Bordetella pertussis harbours a region of 27 contiguous kb, which contains the bvg, fha and flm genes, involved in the co-ordinate regulation of virulence genes, FHA production and fimbriae production, respectively. The linkage of FHA and fimbrial genes has resulted in some confusion concerning the existence and location of genes required for the production of FHA and the function of the fimbrial genes fimB-D, which were proposed to be involved in both FHA and fimbriae biosynthesis. Through the use of non-polar mutations in each of these genes, we found that fimB-D are required for the production of both serotype 2 and 3 fimbriae, but not for FHA biosynthesis. Furthermore, a large open reading frame, designated fhaC, was identified downstream of fimD. It was shown that fhaC is essential for FHA production but not for fimbriae biogenesis. We propose that insertion mutations in fimB-D affect FHA production because of polar effects on fhaC expression. An insertion in the region downstream of fhaC had only a slight effect on FHA and fimbriae production. The fhaC gene product shows homology with ShIB and HpmB, two outer membrane proteins involved in export and activation of the haemolysins, ShIA and HpmA, of Serratia marcescens and Proteus mirabilis, respectively. Homology is also observed between the N-termini of FHA, ShIA and HpmA. Export of the haemolysins requires the Af-termini of these molecules, and when this region was removed from FHA by an in-frame deletion, FHA biosynthesis was abolished. These results suggest that the N-terminus of FHA interacts with FhaC, and that as a result FHA is transported across the outer membrane.
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