Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailDNA immunisation. New histochemical and morphometric data.
Ehirchiou, D.; Zorzi, Willy ULg; Biemans, R. et al

in European Journal of Histochemistry (2002), 46(3), 215-22

Splenic germinal center reactions were measured during primary response to a plasmidic DNA intramuscular injection. Cardiotoxin-pretreated Balb/c mice were immunized with DNA plasmids encodmg or not the ... [more ▼]

Splenic germinal center reactions were measured during primary response to a plasmidic DNA intramuscular injection. Cardiotoxin-pretreated Balb/c mice were immunized with DNA plasmids encodmg or not the SAG1 protein, a membrane antigen of Toxoplasma gondii. Specific anti-SAG1 antibodies were detected on days 16 and 36 after injection of coding plasmids. The results of ELISAs showed that the SAG1-specific antibodies are of the IgG2a class. Morphometric analyses were done on serial immunostained cryosections of spleen and draining or non-draining lymph nodes. This new approach made it possible to evaluate the chronological changes induced by DNA immunisation in the germinal centres (in number and in size). Significant increases in the number of germinal centres were measured in the spleen and only in draining lymph nodes after plasmid injection, the measured changes of the germinal centers appeared to result from the adjuvant stimulatory effect of the plasmidic DNA since both the coding and the noncoding plasmid DNA induced them. No measurable changes were recorded in the T-dependent zone of lymph organs. [less ▲]

Detailed reference viewed: 15 (2 ULg)
Full Text
Peer Reviewed
See detailDNA immunization with plasmids encoding fusion and nucleocapsid proteins of bovine respiratory syncytial virus induces a strong cell-mediated immunity and protects calves against challenge.
Boxus, Mathieu ULg; Tignon, Marylene; Roels, Stefan et al

in Journal of Virology (2007), 81(13), 6879-89

Respiratory syncytial viruses (RSV) are one of the most important respiratory pathogens of humans and cattle, and there is currently no safe and effective vaccine prophylaxis. In this study, we designed ... [more ▼]

Respiratory syncytial viruses (RSV) are one of the most important respiratory pathogens of humans and cattle, and there is currently no safe and effective vaccine prophylaxis. In this study, we designed two codon-optimized plasmids encoding the bovine RSV fusion (F) and nucleocapsid (N) proteins and assessed their immunogenicity in young calves. Two administrations of both plasmids elicited low antibody levels but primed a strong cell-mediated immunity characterized by lymphoproliferative response and gamma interferon production in vitro and in vivo. Interestingly, this strong cellular response drastically reduced viral replication, clinical signs, and pulmonary lesions after a highly virulent challenge. Moreover, calves that were further vaccinated with a killed-virus vaccine developed high levels of neutralizing antibody and were fully protected following challenge. These results indicate that DNA vaccination could be a promising alternative to the classical vaccines against RSV in cattle and could therefore open perspectives for vaccinating young infants. [less ▲]

Detailed reference viewed: 9 (1 ULg)
Full Text
Peer Reviewed
See detailDNA in chromatin: from genome-wide sequence analysis to the modelling of replication in mammals
Arbeodo, Alain; d'Aubenton-Carafa, Y.; Audit, B. et al

in Advances in Chemical Physics (2006), 135

Understanding how chromatin is spatially and dynamically organized in the nucleus of eukaryotic cells and how this affects genome functions is one of the main challenges of cell biology. In that context ... [more ▼]

Understanding how chromatin is spatially and dynamically organized in the nucleus of eukaryotic cells and how this affects genome functions is one of the main challenges of cell biology. In that context the role of the DNA sequence itself in these condensation- decondensation processes is still debated. In this chapter, we explore large-scale nucleotide compositional fluctuations along the human genome through the optics of the wavelet transform microscope. Analysis of the GC content and of the TA and GC skews re- veals the existence of rhythms with characteristic fundamental frequencies that enlighten a remarkable cooperative organization of gene location and orientation. We describe a multi-scale methodology that allows us to predict 1012 replication origins in the 22 hu- man autosomal chromosomes. We present a model of replication with well-positioned replication origins and random termination sites that accounts for the highly relaxational nature of the oscillations observed in the skew profiles. We emphasize these putative replication initiation zones as regions where the chromatin fiber is likely to be more open so that DNA be more easily accessible. We show that, in the crowded environment of the cell nucleus, the presence of these intrinsic decondensed structural defects actually pre- disposes the fiber to spontaneously form multi-looped rosette-like structures that provide an attractive description of genome organization into replication foci that are observed in interphase mammalian nuclei as stable autonomous chromatin domains favoring com- partmentalized DNA replication and gene expression. New experimental perspectives are discussed. [less ▲]

Detailed reference viewed: 15 (5 ULg)
Peer Reviewed
See detailDNA interaction properties and topoisomerase I poisoning efficiencies of a new series of aza-indolocarbazole derivatives
Peixoto, Paul ULg; Hildebrand, Marie Paule; Baldeyrou, Brigitte et al

Poster (2006, June 02)

Detailed reference viewed: 10 (1 ULg)
Full Text
Peer Reviewed
See detailThe DNA intercalating alkaloid cryptolepine interferes with topoisomerase II and inhibits primarily DNA synthesis in B16 melanoma cells.
Bonjean, K.; De Pauw-Gillet, Marie-Claire ULg; Defresne, Marie-Paule ULg et al

in Biochemistry (1998), 37(15), 5136-46

Cryptolepine hydrochloride is an indoloquinoline alkaloid isolated from the roots of Cryptolepis sanguinolenta. It is characterized by a multiplicity of host-mediated biological activities, including ... [more ▼]

Cryptolepine hydrochloride is an indoloquinoline alkaloid isolated from the roots of Cryptolepis sanguinolenta. It is characterized by a multiplicity of host-mediated biological activities, including antibacterial, antiviral, and antimalarial properties. To date, the molecular basis for its diverse biological effects remains largely uncertain. Several lines of evidence strongly suggest that DNA might correspond to its principal cellular target. Consequently, we studied the strength and mode of binding to DNA of cryptolepine by means of absorption, fluorescence, circular, and linear dichroism, as well as by a relaxation assay using DNA topoisomerases. The results of various optical and gel electrophoresis techniques converge to reveal that the alkaloid binds tightly to DNA and behaves as a typical intercalating agent. In DNAase I footprinting experiments it was found that the drug interacts preferentially with GC-rich sequences and discriminates against homo-oligomeric runs of A and T. This study has also led to the discovery that cryptolepine is a potent topoisomerase II inhibitor and a promising antitumor agent. It stabilizes topoisomerase II-DNA covalent complexes and stimulates the cutting of DNA at a subset of preexisting topoisomerase II cleavage sites. Taking advantage of the fluorescence of the indoloquinoline chromophore, fluorescence microscopy was used to map cellular uptake of the drug. Cryptolepine easily crosses the cell membranes and accumulates selectively into the nuclei rather than in the cytoplasm of B16 melanoma cells. Quantitative analyses of DNA in cells after Feulgen reaction and image cytometry reveal that the drug blocks the cell cycle in G2/M phases. It is also shown that the alkaloid is more potent at inhibiting DNA synthesis rather than RNA and protein synthesis. Altogether, the results provide direct evidence that DNA is the primary target of cryptolepine and suggest that this alkaloid is a valid candidate for the development of tumor active compounds. [less ▲]

Detailed reference viewed: 75 (1 ULg)
Full Text
Peer Reviewed
See detailDNA intercalation, topoisomerase II inhibition and cytotoxic activity of the plant alkaloid cryptolepine
Bailly, Christian; Laine, W.; Baldeyrou, B. et al

in Anti-Cancer Drug Design (2000), 15(3), 191-201

Cryptolepine and neocryptolepine are two indoloquinoline alkaloids isolated from the roots of the African plant Cryptolepis sanguinolenta. Both drugs have revealed antibacterial and antiparasitic ... [more ▼]

Cryptolepine and neocryptolepine are two indoloquinoline alkaloids isolated from the roots of the African plant Cryptolepis sanguinolenta. Both drugs have revealed antibacterial and antiparasitic activities and are strongly cytotoxic to tumour cells. We have recently shown that cryptolepine can intercalate into DNA and stimulates DNA cleavage by human topoisomerase II. In this study, we have investigated the mechanism of action and cytotoxicity of neocryptolepine, which differs from the parent isomer only by the orientation of the indole unit with respect to the quinoline moiety. The biochemical and physicochemical results presented here indicate that neocryptolepine also intercalates into DNA, preferentially at GC-rich sequences, but exhibits a reduced affinity for DNA compared with cryptolepine. The two alkaloids interfere with the catalytic activity of human topoisomerase II but the poisoning activity is slightly more pronounced with cryptolepine than with its isomer. The data provide a molecular basis to account for the reduced cytotoxicity of neocryptolepine compared with the parent drug. [less ▲]

Detailed reference viewed: 55 (2 ULg)
Full Text
Peer Reviewed
See detailDNA methylation and cancer diagnosis: new methods and applications.
Dehan, Pierre ULg; Kustermans, Gaëlle ULg; Guénin, Samuel ULg et al

in Expert Review of Molecular Diagnostics (2009), 9(7), 651-7

Methylation of cytosines in cytosine-guanine (CpG) dinucleotides is one of the most important epigenetic alterations in animals. The presence of methylcytosine in the promoter of specific genes has ... [more ▼]

Methylation of cytosines in cytosine-guanine (CpG) dinucleotides is one of the most important epigenetic alterations in animals. The presence of methylcytosine in the promoter of specific genes has profound consequences on local chromatin structure and on the regulation of gene expression. Changes in DNA methylation play a central role in carcinogenesis. Hypermethylation and consecutive transcriptional silencing of tumor-suppressor genes has been documented in numerous cancers. The identification of target genes silenced by this modification has a great impact on diagnosis, classification, definition of risk groups and prognosis of cancer patients. Here we outline genome-wide techniques aiming at the identification of relevant methylated promoters. Methods and applications allowing clinicians to monitor the methylation of target genes will be also reviewed. [less ▲]

Detailed reference viewed: 91 (18 ULg)
Full Text
See detailDNA methylation and expression of prolactin and growth hormone genes in a rat pituitary strain selected on steroid-depleted medium
Laverriere, J. N.; Muller, Marc ULg; Tougard, C. et al

in MacLeod, R. M.; Thorner, M. O.; Scapagnini, U. (Eds.) Prolactin, basic and clinical correlates (1985)

Detailed reference viewed: 12 (3 ULg)
Full Text
Peer Reviewed
See detailDNA methyltransferase DNMT3b protein overexpression as a prognostic factor in patients with diffuse large B-cell lymphomas
Amara, Khaled; Ziadi, Sonia; Hachana, Mohamed Ridha ULg et al

in Cancer Science (2010), 101(7), 1722-1730

Detailed reference viewed: 22 (1 ULg)
Full Text
Peer Reviewed
See detailDNA polymorphism detection in Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae): potential use in stored product pest management
Braet, Yves; Haubruge, Eric ULg

in DNA Sequence : The Journal of DNA Sequencing & Mapping (1995), 6

Detailed reference viewed: 12 (2 ULg)
Full Text
Peer Reviewed
See detailDNA promoter hypermethylation of BLU gene in invasive breast ductal carcinoma in Tunisia
Hachana, Mohamed Ridha ULg; Trimeche, Mounir; Amara, Khaled et al

in Virchows Archiv : An International Journal of Pathology (2007)

Detailed reference viewed: 11 (0 ULg)
Full Text
Peer Reviewed
See detailDNA released from dying host cells mediates aluminum adjuvant activity
Marichal, Thomas ULg; Ohata, Keiichi; Bedoret, Denis et al

in Nature Medicine (2011), 17

Aluminum-based adjuvants (alum) are widely used in human vaccination, although little is understood of their mechanisms of action. Here, we report that, in mice, alum causes the release of host cell DNA ... [more ▼]

Aluminum-based adjuvants (alum) are widely used in human vaccination, although little is understood of their mechanisms of action. Here, we report that, in mice, alum causes the release of host cell DNA, which acts as a potent endogenous immunostimulatory signal mediating alum adjuvant activity. Furthermore, we propose that host DNA signaling differentially regulates IgE and IgG1 production upon alum immunization. Indeed, we support that host DNA induces primary B cell responses, including IgG1 production, through Interferon Response Factor (Irf) 3-independent mechanisms, and 'canonical' type 2 T cell responses associated with IgE isotype switching and peripheral effector responses through Irf3-dependent mechanisms. The finding that host cell DNA is a damage-associated molecular pattern relaying alum adjuvant activity may thus help in the comprehension of the mechanisms of action of current vaccines and in the design of novel adjuvants. [less ▲]

Detailed reference viewed: 133 (27 ULg)
See detailDNA repair mechanisms: implication in cancer
Habraken, Yvette ULg

Post doctoral thesis (1999)

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailDNA replication timing data corroborate in silico human replication origin predictions
Audit, B.; Nicolay, Samuel ULg; Huvet, M. et al

in Physical Review Letters (2007), 99

We develop a wavelet-based multiscale pattern recognition methodology to disentangle the replication- from the transcription-associated compositional strand asymmetries observed in the human genome ... [more ▼]

We develop a wavelet-based multiscale pattern recognition methodology to disentangle the replication- from the transcription-associated compositional strand asymmetries observed in the human genome. Comparing replication skew profiles to recent high-resolution replication timing data reveals that most of the putative replication origins that border the so-identified replication domains are replicated earlier than their surroundings whereas the central regions replicate late in the S phase. We discuss the implications of this first experimental confirmation of these replication origin predictions that are likely to be early replicating and active in most tissues. [less ▲]

Detailed reference viewed: 18 (4 ULg)
Full Text
Peer Reviewed
See detailDNA sequences coding for the F18 fimbriae and AIDA adhesin are localized on the same plasmid in Escherichia coli isolates from piglets
Mainil, Jacques ULg; Jacquemin, E.; Pohl, P. et al

in Veterinary Microbiology (2002), 86

Detailed reference viewed: 6 (0 ULg)
Full Text
Peer Reviewed
See detailDNA vaccination for the priming of neutralizing antibodies against non-immunogenic STa enterotoxin from enterotoxigenic Escherichia coli
Ruth, Nadia ULg; Mainil, Jacques ULg; Roupie, Virginie et al

in Vaccine (2005), 23(27), 3618-3627

In order to test the use of DNA vaccination for its capacity to induce antibodies against the non-immunogenic heat-stable enterotoxin STa from Escherichia coli, BALB/c mice were immunized with plasmid DNA ... [more ▼]

In order to test the use of DNA vaccination for its capacity to induce antibodies against the non-immunogenic heat-stable enterotoxin STa from Escherichia coli, BALB/c mice were immunized with plasmid DNA encoding hybrid proteins made by the insertion of wild type STa or insertion of the Cys6Ala, Cys17Ala and Cys6Ala-Cys17Ala STa mutants at positions 195 or 216 of the TEM-1 beta-lactamase. No STa specific antibodies could be detected after three plasmid injections, but a subsequent boost with native STa peptide was capable of inducing low levels of neutralizing antibodies, as tested in the suckling mouse assay. Highest STa specific responses were found in mice primed with the double mutated STa inserted in position 195. This plasmid induced highest T-cell responses to the TEM-1 protein, indicating that priming of helper T-cell responses to the carrier protein was essential. Mixed IgG1/IgG2a isotypes also reflected this T helper 1 type priming. Moreover, insertion into loop A of the TEM-1 carrier may be more suitable than insertion into loop B, because of reduced competition between carrier and hapten B cell responses. [less ▲]

Detailed reference viewed: 64 (10 ULg)
Peer Reviewed
See detailDNA-binding mechanism of the Escherichia coli Ada O(6)-alkylguanine-DNA alkyltransferase.
Verdemato, P. E.; Brannigan, J. A.; Damblon, Christian ULg et al

in Nucleic Acids Research (2000), 28(19), 3710-8

The C-terminal domain of the Escherichia coli Ada protein (Ada-C) aids in the maintenance of genomic integrity by efficiently repairing pre-mutagenic O:(6)-alkylguanine lesions in DNA. Structural and ... [more ▼]

The C-terminal domain of the Escherichia coli Ada protein (Ada-C) aids in the maintenance of genomic integrity by efficiently repairing pre-mutagenic O:(6)-alkylguanine lesions in DNA. Structural and thermodynamic studies were carried out to obtain a model of the DNA-binding process. Nuclear magnetic resonance (NMR) studies map the DNA-binding site to helix 5, and a loop region (residues 151-160) which form the recognition helix and the 'wing' of a helix-turn-wing motif, respectively. The NMR data also suggest the absence of a large conformational change in the protein upon binding to DNA. Hence, an O:(6)-methylguanine (O:(6)meG) lesion would be inaccessible to active site nucleophile Cys146 if the modified base remained stacked within the DNA duplex. The experimentally determined DNA-binding face of Ada-C was used in combination with homology modelling, based on the catabolite activator protein, and the accepted base-flipping mechanism, to construct a model of how Ada-C binds to DNA in a productive manner. To complement the structural studies, thermodynamic data were obtained which demonstrate that binding to unmethylated DNA was entropically driven, whilst the demethylation reaction provoked an exothermic heat change. Methylation of Cys146 leads to a loss of structural integrity of the DNA-binding subdomain. [less ▲]

Detailed reference viewed: 11 (0 ULg)