Search Results - (Author, Cooperation:R. Rappuoli)

2012-06-23

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Cross Protection ; Global Health ; Humans ; *Influenza A Virus, H5N1 Subtype/immunology/pathogenicity ; *Influenza Vaccines/administration & dosage/immunology/supply & distribution ; Influenza, Human/*epidemiology/*prevention & control/transmission/virology ; Mass Vaccination ; Pandemics/*prevention & control ; Vaccines, DNA

2011-05-27

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

*AIDS Vaccines/chemistry/immunology ; Animals ; Antigens/chemistry/immunology ; Clinical Trials as Topic ; HIV Infections/epidemiology/immunology/prevention & control ; Humans ; Malaria/epidemiology/immunology/parasitology/prevention & control ; *Malaria Vaccines/chemistry/immunology ; Systems Biology/trends ; Tuberculosis/epidemiology/immunology/microbiology/prevention & control ; *Tuberculosis Vaccines/chemistry/immunology

1365-3083

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The transforming protein E7 of human papilloma virus type 16 can stimulate cytotoxic T lymphocytes (CTL) which can protect experimental animals against growth of E7 expressing tumour cells. In this study we compared CTL responses in mice immunized with either E7 protein in MF59 adjuvant or with recombinant vaccinia virus expressing E7 (Vac-E7). We have chosen H-2d mice because no E7-specific CTL responses have been described in this MHC haplotype. Immunization of these mice with Vac-E7 generated CTL which lysed target cells infected with Vac-E7 or transfected with the E7 gene. CTL from mice immunized with E7 protein in MF59 adjuvant showed specificity for the same target cells. Antibody blocking experiments revealed that both immunization with Vac-E7 and E7 protein stimulated CD8+ effector CTL. The find specificity of CTL induced by the two immunization protocols was similar. A major CTL epitope was mapped to the carboxyl terminal amino acids 48–98 of the E7 protein. Peptide isolation from E7 expressing cells followed by HPLC separation indicated that CTL induced by immunization with protein and Vac-E7 recognized the same HPLC purified peptide fractions. Together, the study suggests that vaccines based on protein can activate CTL with similar fine specificity to CTL induced by vaccines based on recombinant vaccinia virus.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

The expression of the virulence-associated genes in Bordetella species is co-ordinately regulated by the gene products encoded by the bvg locus. In Bordetella pertussis the expression of this locus is regulated by the P1, P2, P3 and P4 promoters which are located in a 350bp DNA fragment also containing the PFHA promoter. Here we report the transcriptional regulation of the bvg locus and the fha gene in Bordetella paraper-tussis and a sequence analysis of the byg-regulated promoters. The Pp1, Pp2, Pp4 and PpFHA promoters are indistinguishable, both in transcription initiation sites and environmental regulation, from the corresponding promoters of B. pertussis, while the Pp3 promoter is not active. Sequence homologies from nine bvg-regulated promoters show a conserved dinucleotide, 5′-TG-3′, at approximately one turn of helix upstream of the -10 5′-A.AaTat-3’region, and a 5′-TTTCC-3’sequence in the -90 region. Since the nucleotide sequence of the inactive Pp3 promoter shows several base substitutions with respect to the found sequence homologies, it is likely that some of these bases play an essential role in promoter activity.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

The nucleotide sequence of the structural gene for filamentous haemagglutinin (FHA), fhaB, a crucial adherence factor for Bordetella perfussis, has been determined. Its 10774 nucleotides are far more than necessary to encode the 220kD biologically active, mature polypeptide product, suggesting a role for co-or post-translational processing. Fusion proteins derived from various portions of the fhaB open reading frame (ORF) were used to generate polyclonal antisera. Western immunoblot analysis of purified FHA and Bordetella sp. whole cell extracts with these antisera indicated that the 220kD product is encoded by the 5 portion of the ORF and that the smaller polypeptide species are breakdown products of this polypeptide. These data, as well as N-terminal amino acid sequencing of the major polypeptide species, suggest a scheme for the proteolytic processing of an FHA precursor polypeptide.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

A search for pilin genes in a Bordetella pertussis (Bp) genomic library has led to the identification of several clones which hybridize to synthetic oligonucleotides with sequences derived from amino acid sequences of Bp fimbrial subunits. One of these clones (corresponding to a gene we have named fimX) contains an open reading frame encoding a protein with a molecular weight of about 20 kD and a sequence similar but not identical to the fimbrial subunit fim2 and to other fimbrial protein sequences. In this communication we present the cloning and nucleotide sequence of the fimX gene and its homology to the fim2 gene. A genomic analysis on the positional relationship between the two genes is also presented.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Bafilomycin A1, a specific inhibitor of the vacuolar-type H+-ATPase, responsible for acidification of intra-cellular compartments, prevents the vacuolization of Hela cells induced by H. pylori, with an inhibitory concentration giving 50% of maximal (ID50) of 4 nM. Bafilomycin A1 is also very efficient in restoring vacuolated cells to a normal appearance. The vacuolating activity of Helicobacter pylori is not inhibited by a series of specific inhibitors of vacuolar H+-ATPases. These findings indicate that a transmembrane pH gradient is needed for the formation and growth of vacuoles caused by the bacterium and that this pH gradient is due to the activity of a vacuolar ATPase proton pump of HeLa cells.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

The bvg locus contains two genes, bvgA and bvgS, which control the expression of the virulence-associated genes in Bordetella species by a system similar to the two-component systems used by a variety of bacterial species to respond to environmental stimuli. We determined the nucleotide sequence of the bvg loci of Bordetella parapertussis and Bordetella bronchiseptica and compared them with the previously determined sequence of Bordetella pertussis. The nucleotide and amino acid sequences of the bvg loci of these species are well conserved in those regions coding for the protein domains which have putative kinase and DNA-binding activities. In marked contrast, the region of BvgS that codes for the protein domain with putative sensor activity shows a high degree of variability. In total, we find 198 base-pair changes in the bvg loci of B. parapertussis and B. bronchiseptica relative to the bvg locus of B. pertussis. One hundred and seventy-three of these base-pair changes are identical in S. parapertussis and B. bronchiseptica. Tills confirms our previous observation that B. parapertussis and B. bronchiseptica are more related to each other than to B. pertussis. We have mapped the mutations that cause phase changes in B. bronchiseptica and we have found that in three cases these are due to spontaneous deletions in the bvgS gene.The wild-type bvg locus present on a multicopy plasmid cannot complement avirulent derivatives of B. bronchiseptica to wild-type levels, but it can do so when the bvgA gene on the plasmid is inactivated. This suggests that hyperexpression of bvgA down-regulates the bvg system.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Pertussis toxin (PT) is the major virulence factor of Bordetella pertussis. The cloning and nucleotide sequencing of the PT genes from B. pertussis, Bordetella parapertussis and Bordetella bronchiseptica has elucidated the evolution of the Bordetella species and allowed considerable advances towards the understanding of their gene expression and the development of safer vaccines against pertussis.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

The nucleotide sequence of the pertussis toxin operon of Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica, has shown that the last two species contain many common mutations and are likely to derive from a common ancestor (Arico and Rappuoli, 1987). To elucidate further the evolutionary relationships between the Bordetella species, we have cloned and sequenced the promoter region and the gene coding for the S1 subunit of pertussis toxin from additional B. pertussis strains, such as the type strain BP 18323 and two recent clinical isolates, namely strain BP 13456 from Sweden and strain BP SA1 from Italy. While the strains BP SA1 and BP 13456 are shown to differ from the published B. pertussis sequences by only one base pair, the type strain BP 18323 contains a total of 11 base-pair substitutions. Remarkably, 9 of the 11 substitutions found in BP 18323 are also common to B. parapertussis and B. bronchiseptica, strongly suggesting that this strain derives from the same ancestor as B. parapertussis and B. bronchiseptica.Computer analysis of the sequence data allows the construction of an evolutionary ‘tree’ showing that the B. pertussis strains are very homogeneous and significantly distant from B. parapertussis and B. bronchiseptica. Therefore the proposed conversion from B. parapertussis to B. pertussis appears highly improbable.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Summary Five ADP-ribosylating bacterial toxins, pertussis toxin, cholera toxin, diphtheria toxin, Escherichia LT toxin and Pseudomonas exotoxin A, show significant homology in selected segments of their sequence. Site-directed mutagenesis and chemical modification of residues within these regions cause loss of catalytic activity and of NAD binding. On the basis of these results and of molecular modelling based on the three-dimensional structure of exotoxin A, the geometry of an NAD binding site common to all the toxins is deduced and described in the paper. For diphtheria toxin, sequence similarity with exotoxin A is such that its preliminary structure can be computed by molecular modelling, whereas for the other toxins similarity appears to be restricted to the NAD binding site. Moreover, an analysis of molecular fitting of the NAD molecule into its binding cavity suggests a new model for the conformation of the bound NAD that better accounts for all available experimental information.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Tn5 mutants of B. pertussis. Comparison of various functions of the vir loci of B. bronchiseptica and B. pertussis revealed some interesting differences in the coordinate regulation of virulence factors.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Bacteria can respond to a variety of environmental stimuli by means of systems generally composed of two proteins. The first protein (sensor or transmitter) is usually a transmembrane protein with cytoplasmic and extracytoplasmic domains. The extracytoplasmic domain (sensor) senses the environment and transfers the signal through the transmembrane domain to the cytoplasmic domain (transmitter), which has kinase activity. The second protein is located in the cytoplasm and contains an amino-terminal domain (receiver), which can be phosphorylated by the transmitter, and a carboxy-terminal region (regulator), which regulates gene expression by binding to DNA. The transmitter and receiver modules (the kinase and its target) are conserved in all signal-transducing systems and are the‘core structure’of this two-component system. The sensors and the regulators vary according to the stimuli they respond to and the DNA structure they interact with. On the basis of their sequence homology, the proteins belonging to such two-component systems can be classified into different families, which are summarized in this review.

Electronic Resource

1546-1696

Nature Archives 1869 - 2009

Biology

Process Engineering, Biotechnology, Nutrition Technology

[Auszug] Antigenic determinants are often composed of discontiguous polypeptide segments, adjacent on protein surfaces, which are difficult to map by conventional techniques. Here we show that although monoclonal antibodies did not recognize recombinant molecules containing only the aminoterminal or only ...

Electronic Resource

1546-1696

Nature Archives 1869 - 2009

Biology

Process Engineering, Biotechnology, Nutrition Technology

[Auszug] A Corynebacterium diphtheriae strain, containing two copies of the corynephage β45 genome integrated into its chromosome, has been isolated and characterized. This strain produces and secretes into the medium large amounts of diphtheria toxoid CRM45, a non toxic, prematurely terminated ...

Electronic Resource

0378-1119

Pathogenic bacteria ; bvg locus ; environmental transcription control ; two-component system

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

0003-2697

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

0014-5793

Diphtheria toxin ; Lipid interaction ; Toxin mutant

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

0014-5793

Diphtheria toxin ; Monoclonal antibody ; Mutant structure

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource